Psy3242 - User contributions [en]

Phantom limbs

Cmcfall — Mon, 28 Apr 2008 14:24:09 GMT

Cmcfall:

[[Category:Neuropsychological syndromes]]

==Overview==

Phantom limbs is a disorder of peripersonal space, in which deficits in the spatial boundary of the visual receptive fields are observed. Most notably, it refers to a sense of outstanding and often painful feeling (98% of reported cases) from an amputated body part, such as the arms or legs, which is usually most pronounced following surgery and becomes lessened overtime (Silvano, Berger, Keith, & Brodie, 1974-1986). These sensations are not limited to pain, but also include touch, temperature, wetness, and movement that arise from the no longer existent body part (Stirling, 65). It should also be noted that this phenomenon is not metaphorical in nature, but rather a sensation that is actually felt by such individuals. In fact, the realistic nature of phantom limbs is such that a patient may actually forget that a body part has been removed and attempts to use the missing limb have been widely reported (Stirling, 66). The patient also tends to exhibit a greater conscious awareness of the phantom than the opposite, intact limb (Silvano & Reiser, 1974-1986). The three most common types of the phantom are: a mild, tingling feeling; a momentary “pins and needles” sensation; and painful feelings such as “twisting,” “burning,” “itching,” and “pulling” (Silvano & Reiser, 1974-1986).

As mentioned, most individuals experience pain that can be modified or reduced via surgical procedures, but these operations have often failed to fully eliminate such displeasure (Silvano & Reiser, 1974-1986). The ineffectiveness to diminish painful phantom limb experiences was further explored as anecdotal evidence was collected to provide insight about the underlying mechanisms of this phenomenon. Moreover, case reports have shown that stimulation of body regions aligned with the cortical receptive fields adjacent to the amputated limb can elicit the phantom experience (Stirling, 66). [[Vilayanur Ramachandran]] explained the effects of such experiences by proposing that sensory inputs travel to both target and neighboring regions and that normally, the adjacent regions are inhibited by direct inputs to the region. However, when these inputs are absent, commonly referred to as lateral disinhibition, the nearby regions now receive the cortical inputs, thereby evoking the phantom limb phenomenon (Stirling, 67). While [[Vilayanur Ramachandran]]’s assertion alone cannot account for all aspects of the experience, these findings not only highlight the need to establish methods of recovery, but they also serve as reminder that the developmental aspect of plasticity can still occur, even in mature adults (Stirling, 68).

[[Image:phantomlimbpain.gif]]

==Neural Plasticity==

[[Vilayanur Ramachandran]] (1993) reported plastic changes that were observed in the visual cortex of the brain and referred to this occurrence as the “filling in” phenomenon, in which the loss of visual abilities (e.g. scotomas) caused rapid changes in the reorganization of the primary visual receptive fields. These findings led the researcher to question similar effects of other adult somatosensory pathways, including touch and hearing. Earlier studies found that after long durations of amputation, the cortical area initially corresponding to the hand was now replaced by sensory input from the ipsilateral face region. Thus, the results of these studies coupled with Ramachandran’s previous experiment generated the remapping hypothesis, which asserts the ability of the receptive fields to be temporarily expanded to proximal areas due to the “unmasking” of pre-existing neural connections, rather than the development or sprouting of new ones ([[Ramachandran]], 1993).

Results of the study on individuals with phantom limbs, revealed a one-to-one correspondence between points on the patient’s fingers as well as on the face, which were not randomly represented, but observed on the lower face region and the area near deafferentation ([[Ramachandran]], 1993). Additionally, it was further suggested that complex sensations distal from the region of amputation could be referred, which occur at a rapid rate of reorganization. Thus, modality-specific “rewiring” can effectively occur even after short periods of stimulus deprivation, thereby supporting Ramachandran’s hypothesis that phantom limb experience arises from spontaneous activity of tissues in the face and those near the amputated limb ([[Ramachandran]], 1993). It was also thought that reafferance signals are combined with motor commands that are then sent to the muscle(s) of the phantom limb and to some degree, from neuromas, or tumors that are comprised of nerve tissues ([[Ramachandran]], 1993). The information from these sources is lastly processed in the parietal cortex, which gives rise to the experience, where an image of the nonexistent body part persists. However, in response to the researcher’s own assertions, extensive studies investigating the biological, pre-existing neural connections have failed to find significant results that would support the “unmasking” hypothesis [[Ramachandran]] proposed, thereby giving greater rise to the sprouting hypothesis. If such sprouting were the case, these growths would require precise and rapid cortical reorganization to enable topography to take place as well as the occurrence of complex sensations such as “gripping,” or “trickling” ([[Ramachandran]], 1993). While this study proved to be somewhat inconclusive in that the neither of the competing hypotheses was firmly established, the rapid changes in the topographical maps implied the need for future revision of the stable or unchanging views of cortical receptive fields.

Later, [[Ramachandran]] and Rogers-Ramachandran (2000) further explored the remapping hypothesis and indeed found that unmasking of pre-existing neural connections can be referred even hours after amputation. Similar to the results in the abovementioned study, an earlier experiment on adult monkeys revealed the topographic reorganization when a stimulus was presented to a side of the face that corresponded to the hand in the cortical somatotopic map. Following this finding, magnetoencephalographic experiments showed similar results in the adult human cortex, in that the referred feelings were modality-specific ([[Ramachandran]] & Rogers-Ramachandran, 2000). For instance, sensations that were delivered to the lower face region were also felt on the phantom limb. In addition, when other parts of the body were similarly stimulated, these sensations were not as pronounced on the phantom; however, evidence showed that a second topographical map was constructed close to the missing body part. Therefore, these results provide evidence for the remapping hypothesis, where sensations occur as a result of the unmasking of pre-existing neural connections, as shown in the rapid topographical reorganization; a finding that was previously challenged ([[Ramachandran]] & Rogers- Ramachandran, 2000).

This study also highlighted the role of the conscious experience in brain activity, in that patients initially felt sensations in both the hand and the face, apparently due to the separate activation of these two regions. However, overtime the patient would begin to experience a feeling on the just the face when the hand was touched. This gives rise to a possible “cortical overshooting” during mapping reorganization, so that sensation from the hand is suppressed or masked ([[Ramachandran]] & Rogers-Ramachandaran, 2000). Finally, the researchers reported Mirror box experiments, where a patient would place the intact body part in a location that corresponded to the represented limb. Thus, the visual illusion that the phantom limb had been resurrected provided visual feedback that enabled the troubled patient to relieve any reported displeasure that had been previously experienced ([[Ramachandran]] & Rogers-Ramachandran, 2000). The importance of these studies showed the interaction between visual and somatosensory modalities, which deal with back-and-forth exchanges, rather than the initially proposed hierarchical neural model. Furthermore, these mirror image studies implied that body image is a malleable, internal construct that is also subject to change, despite its seemingly rigid and fixed appearance ([[Ramachandran]] & Rogers-Ramachandran, 2000).

==Body Image==

Body image refers to the internal and actual or idealized image that manifests itself in ways that shape an individual’s personality, self-esteem, and overall psychosocial well-being. In phantom limbs patients, the cerebral representation can be reorganized, so that the phantom is modified and sometimes even dissipated. Often times though, amputation can lead to a distorted body image that is accounted for in emotional, perceptual, and psychosocial reactions (Silvano & Reiser, 1974-1986). This sudden change not only leads to a misrepresentation of the self, but also arouses varying levels of anxiety in such patients. Additionally, denial is a common defense mechanism that cannot only result in failure to report a phantom limb, but also an inability to reorganize an individual’s body image, such that recovery and rehabilitative measures cannot be effectively taken. Consequently, this maladaptation can subsequently lead to embodiment of psychopathological characteristics, which include, but not are not limited to, depression and magical thinking (Silvano & Reiser, 1974-1986). Therefore, attempts to modify the phantom limb can only be successful depending on the relational meaning of the body part to the patient. In other words, if an amputee is unwilling to accept the present body structure, as is, this perceived defect is fully capable of interfering with motivation and recovery as a result of this disturbance (Silvano & Reiser, 1974-1986). Therefore, the unstable nature of a patient’s body image should be fully accounted for in evaluation and treatment of such patients.

[[Image:Phantomlimbs1.jpg]]

==Treatment==

Successful treatment of the disturbed body image arising from the phantom limb phenomenon is dependent upon the current body of knowledge, which unfortunately, has been inadequately implemented in the present social system (Silvano & Reiser, 1974-1986). The ways in which social life is constructed can therefore profoundly affect the self-esteem, or the manner in which a patient perceives him/herself. In cases where the social structure has failed to provide supportive measures, it is vitally crucial for rehabilitative services to appropriately develop procedures that allow for ego enhancement (Silvano & Reiser, 1974-1986). The patient should be made aware of the most commonly reported phantom experiences, and fears and desires about the amputated body part should be addressed. Family, friends, and other environmental influences should also be expected to appropriately respond to such patients, for several studies have shown the detrimental effects that phantom experiences can have on body image and consequently, personality and overall psychological structure and functioning (Silvano & Reiser, 1974-1986). Therefore, these individuals should act as support systems, upon which the patient can reliably depend.

In patients who experience chronic pain, the goal of outside resources is to adopt methods of behavioral reinforcement, or operant mechanisms, which can either, prolong or reduce the individual’s expression of pain. These strategies are referred to as Fordyce’s basic principles of behavior modification (Silvano et al., 1974-1986). The approach here is to alter the patient’s behavior such that he/she can focus on engagement in other areas that enable him/her to withdraw from the reported chronic pain and exert more effortful control over these undesirable experiences. While the aforementioned suggestions regarding this phenomenon have been widely reported, the primary emphasis should remain on the reactions of amputated patients to ensure maximum recovery and restoration of a healthy body image (Silvano et al., 1974-1986).

In similar cases of chronic pain, other forms of therapy can be taken. For instance, Sympathetic Blockade refers to the intravenous infusion of guanethidine by closing off circulation. Shortly after, the patient tends to feel less pain that can sometimes result in complete recovery, but should be repeated to guarantee permanent relief (Silvano et al., 1974-1986). Other approaches to these seemingly endless periods of pain include surgical sympathectomy and chemical sympathectomy, in which destruction of the nerves in the sympathetic system can increase blood flow and reduce pain (Silvano et al., 1974-1986). Similarly, electrical stimulation, intense vibration of the stump, and injections of hypertonic saline have also shown to relieve pain, with duration of success remaining largely dependent upon the patient (Silvano et al., 1974-1986).

Finally, the above mentioned study conducted by [[Ramachandran]] and Rogers-Ramachandran (2000) confirmed the temporary, and in some cases permanent, elimination of pain in phantom limbs patients in Mirror box experiments. As previously noted, the ability to project an individual’s intact limb to a corresponding location on the mirror creates the visual illusion of the reported phantom. This visual feedback, in turn, provides these patients with the ability to relieve unwanted sensations (e.g. clenching) pertaining to the non-existent body part ([[Ramachandran]] & Rogers-Ramachandran, 2000). However, Mirror box experiments are susceptible to “placebo effects” in relation to reduction of pain, and so it is evident that studies of double-blind control subjects should be conducted. Nonetheless, whether or not this procedure produces favorable outcomes, it should still be noted that the use of visual feedback enables patients to not only see, but also feel corresponding movements in the reported phantom, which therefore gives rise to the conscious experience of this phenomenon ([[Ramachandran]] & Rogers-Ramachandran, 2000). Disturbances in an individual’s body-image and/or experience of chronic pain have been largely observed in such patients; however, the extent to which these reactions are reported provide profound implications for which therapy methods will produce the most effective results (Silvano & Reiser, 1974-1986).

==References==

Ramachandran, V. S. (1993). Behavioral and magnetoencephalographic correlates of
plasticity in the adult human brain. Proc. Natl. Acad. Sci. USA, 90, 10413-10420.

Ramachandran, V. S., & Rogers-Ramachandran, D. (2000). Phantom limbs and neural
plasticity. Archives of Neurology, 57, 317-320.

Silvano, A., & Reiser, M. F. (Eds.). (1974-1986). American handbook of psychiatry: Organic disorders and psychosomatic medicine (2nd ed., Vols. 1-8). New York, NY: Basic Books, Inc., Publishers.

Silvano, A., Berger, P. A., Keith, H., & Brodie, H. (Eds.). (1974-1986). American
handbook of psychiatry: Biological psychiatry (2nd ed., Vols. 1-8). New York, NY: Basic Books, Inc., Publishers.

Stirling, J. (2002). Introducing Neuropsychology. New York, NY: Psychology Press.

Synesthesia

Cmcfall — Sun, 27 Apr 2008 23:11:16 GMT

Cmcfall:

[[Category:Neuropsychological syndromes]]

http://www.lurj.org/vol2n1/synesthesia-fig1.jpg

*Visual Search Efficiency from Synesthetic Colors

==External Links==

http://youtube.com/watch?v=KApieSGlyBk&feature=related

Synesthesia

Cmcfall — Sun, 27 Apr 2008 23:10:20 GMT

Cmcfall:

[[Category:Neuropsychological syndromes]]

http://www.lurj.org/vol2n1/synesthesia-fig1.jpg

*Visual Search Efficiency from Synesthetic Colors

Synesthesia

Cmcfall — Sun, 27 Apr 2008 22:59:26 GMT

Cmcfall:

[[Category:Neuropsychological syndromes]]

http://www.lurj.org/vol2n1/synesthesia-fig1.jpg

[[Image:synesthesia1.gif]]

Wisconsin card sort test

Cmcfall — Sun, 27 Apr 2008 22:58:41 GMT

Cmcfall:

[[Category:Neuropsychological methods]]

== Links ==

[http://www.encyclopedia.com/doc/1O87-WisconsinCardSortingtest.html Definition]

[[Image:wisconsincardsort.jpg]]

Amygdala

Cmcfall — Sun, 27 Apr 2008 22:57:14 GMT

Cmcfall:

[[Category:Brain areas]]

==Overview==

The amygdala represents an anatomical structure of the brain that is involved in a range of behavioral and mental conditions (LeDoux, 2007). Previously, this area had received little scientific recognition, but now it is one of the most extensively studied brain regions. The name “amygdala” is rooted in Greek and refers to the almond-shaped structure located bilaterally within the temporal lobes of the limbic system (LeDoux, 2007). Most individuals assume the amygdala to be comprised of a single mass; however, its composition includes several nuclei, which can be found in species of higher cognitive functioning, including humans and primates. Consistent with this view, it can be argued that the amygdala is not a unitary structure or function, but rather accords several regions that contribute to cognitive functions of other areas in the brain (LeDoux, 2007). In specific, the lateral and basal amygdala are viewed as nuclear extensions of the cortex, while the central and medial nuclei are part of ventral expansions of the striatum and each of these areas can further be divided into subnuclei, which are all relevant to the study of this anatomical region. For example, the dorsal subcomponent of the lateral nucleus is said to be involved in varying aspects of fear memory (LeDoux, 2007).

[[Image:Amygdala-hippocampus.jpg]]

==Connectivity==

The importance of connectivity points to the ability for specific areas of the brain to make connections with other related regions for the purpose of function (LeDoux, 2007). For instance, the lateral amygdala is responsible for receiving stimulatory input from different sensory systems, such as the visual, somatosensory, olfactory, and auditory modalities (LeDoux, 2007). These inputs are then transferred and consummated in the dorsal subnucleus. This subregion then relays information to the ventrolateral and medial areas in order to connect with other areas of the amygdala (LeDoux, 2007).
The region most notable in behavioral and physiological output is the central nucleus, in which connections from the medial subarea and other interconnected nuclei (e.g. basal nucleus) are involved, at least for the expression of emotional responses. As previously mentioned, areas in the striatum also connect with the central nucleus in instrumental behaviors (LeDoux, 2007). More specifically, sensory output from the central amygdala to the brainstem results in the management of emotions, but the interconnectivity between the basal subregion and the striatum are responsible for controlling action-based behaviors, like running from a potential marauder. Finally, the extent to which the connections are successful in relaying communication relies on the role of various neurotransmitter systems, such as dopamine and serotonin, thereby resulting in exhibitory and inhibitory behavioral responses (LeDoux, 2007).

[[Image:AmygdalaInputs.jpg]]

==Behavior==

In the early 20th century, observed damage in the temporal lobe showed profound changes in behaviors such as fear and sex-related responses (LeDoux, 2007). After determining that the amygdala played a role in these impairments, the inability to account for the underlying substructures of this area resulted in a body of research that was widely misunderstood. It was not until after the discovery of the amygdala’s subcomponents, in which researchers were able to study specific behavioral functions associated with this region (LeDoux, 2007).

'''Fear'''

Fear has been documented throughout scientific literature and more specifically, use of Pavlovian conditioning (the seemingly innate ability to learn stimulus-response (SR) affiliations when presented with associative stimuli) has been shown to consistently and effectively measure such behavior (LeDoux, 2007). The habituation of these associations, through prolonged exposure, implies the developmental aspect of plasticity to aid in the maintenance of short-term memory. Moreover, when these SR associations are re-presented to an individual, the enduring plasticity reveals storage of the appropriate information to the individual’s long-term memory (LeDoux, 2007).

[[Image:Amygdalafear.jpg]]

'''Other'''

While fear response continues to be the most salient behavioral function associated with the amygdala, other research has pointed out that this region is also involved in other emotions such as aggression, sexuality, and addictive, ingestive behaviors (e.g. eating and drinking). Additionally, the amygdala’s ability to release hormones, through neurotransmitter modalities, to other regions of the brain also influences other specific types of cognition, such as attention, perception, and explicit memory (LeDoux, 2007). In other words, the amygdala’s emotional processing to external stimuli establishes connections with other functions of the brain. As earlier noted, the amygdala plays a role in several psychiatric conditions, like autism, schizophrenia, borderline personality disorder, and depression. More importantly, the amygdala is not the cause of these disorders, but rather alterations in the representation of this region result in specific behavioral changes in these individuals (LeDoux, 2007).

'''Relevant Studies'''

Bechara, Tranel, Damasio, Adolphs, Rockland, and Damasio (1995) studied the double dissociation between conditioning and declarative knowledge in relation to the amygdala and the hippocampus in three patients. In two conditioning experiments, using a skin conductance response (SCR) measure, the researchers found that the patient with bilateral damage to the amygdala was unable to acquire the conditioned autonomic responses to the presented visual or auditory stimuli; however, declarative knowledge of the stimuli was largely spared (Bechara et al., 1995). Conversely, the patient with hippocampal damage was able to acquire the conditioned autonomic responses, but failed to retain declarative knowledge of the material. Lastly, the third patient had damage to both brain areas, resulting in an inability to acquire both conditioned autonomic responses and declarative facts. Consistent with previous research, this study further suggested the role the amygdala plays in associative cues of affect, while the hippocampus is responsible for learning the critical relationships among these cues (Bechara et al., 1995).

A later study conducted by Bechara, Damasio, Damasio, and Lee (1999) focused on the contributions of the amygdala and the ventromedial prefrontal (VMF) cortex in human decision-making. Using the “gambling task” to measure decision-making and a skin conductance response (SCR) instrument, the researchers were able to effectively study a group of patients with bilateral amygdala damage and another group with VMF bilateral damage (Bechara et al., 1999). In a Pavlovian conditioning experiment, participants were also tested for acquisition of a conditioned SCR to paired visual stimuli and an aversive loud noise (Bechara et al., 1999). Results of the study revealed that the two areas have distinct influences on decision-making. More specifically, patients with amygdala damage were unable to produce SCRs on both the “gambling task” as well as the conditioning experiment. The group of individuals with VMF damage were also unable to generate SCRs on the “gambling task,” but were able to produce a response when presented with a reward or punishment (e.g. play money), while the amygdala-damaged patients still failed to produce such a response when they received similar reinforcements (Bechara et al., 1999).

The differences associated with decision-making in the two groups implies potentially bigger consequences for the patients with bilateral amygdala damage, in that the failure to evoke the appropriate somatic state results in impairment of future decision-making tasks that elicit similar somatic affects (Bechara, 1999). In sum, this study paralleled earlier research about the underlying functions of the orbitofrontal cortex and the basolateral amygdala and their association with goal-directed behavior. While both groups of patients showed impairments on similar decision-making tasks, the individuals with bilateral damage to the amygdala are much more susceptible to both psychologically and physically harmful real-life situations, where a decision may be critical (Bechara, 1999). In other words, their overall failure to adequately respond to external stimuli due to alterations in emotional states (e.g. fear), may therefore cause such individuals to choose a course of action, in which an unfavorable outcome could result in devastating mental and/or physical consequences.

'''Interesting fact'''

The amygdala is responsible for the emotional reactions to music.

==References==

Bechara, A., Tranel, D., Damasio, H., Adolphs, R., Rockland, C., & Damasio, A. R.
(1995). Double dissociation of conditioning and declarative knowledge relative
to the amygdala and hippocampus in humans. Science, 269, 1115-1118.

Bechara, A., Damasio, H., Damasio, A. R., & Lee, G. P. (1999). Different contributions
of the human amygdala and ventromedial prefrontal cortex to decision-making.
The Journal of Neuroscience, 19(3), 5473-5481.

LeDoux, J. (2007). The amygdala. Current Biology, 17, 868-874.

Amygdala

Cmcfall — Sun, 27 Apr 2008 22:56:46 GMT

Cmcfall:

[[Category:Brain areas]]

==Overview==

The amygdala represents an anatomical structure of the brain that is involved in a range of behavioral and mental conditions (LeDoux, 2007). Previously, this area had received little scientific recognition, but now it is one of the most extensively studied brain regions. The name “amygdala” is rooted in Greek and refers to the almond-shaped structure located bilaterally within the temporal lobes of the limbic system (LeDoux, 2007). Most individuals assume the amygdala to be comprised of a single mass; however, its composition includes several nuclei, which can be found in species of higher cognitive functioning, including humans and primates. Consistent with this view, it can be argued that the amygdala is not a unitary structure or function, but rather accords several regions that contribute to cognitive functions of other areas in the brain (LeDoux, 2007). In specific, the lateral and basal amygdala are viewed as nuclear extensions of the cortex, while the central and medial nuclei are part of ventral expansions of the striatum and each of these areas can further be divided into subnuclei, which are all relevant to the study of this anatomical region. For example, the dorsal subcomponent of the lateral nucleus is said to be involved in varying aspects of fear memory (LeDoux, 2007).

[[Image:Amygdala-hippocampus.jpg]]

==Connectivity==

The importance of connectivity points to the ability for specific areas of the brain to make connections with other related regions for the purpose of function (LeDoux, 2007). For instance, the lateral amygdala is responsible for receiving stimulatory input from different sensory systems, such as the visual, somatosensory, olfactory, and auditory modalities (LeDoux, 2007). These inputs are then transferred and consummated in the dorsal subnucleus. This subregion then relays information to the ventrolateral and medial areas in order to connect with other areas of the amygdala (LeDoux, 2007).
The region most notable in behavioral and physiological output is the central nucleus, in which connections from the medial subarea and other interconnected nuclei (e.g. basal nucleus) are involved, at least for the expression of emotional responses. As previously mentioned, areas in the striatum also connect with the central nucleus in instrumental behaviors (LeDoux, 2007). More specifically, sensory output from the central amygdala to the brainstem results in the management of emotions, but the interconnectivity between the basal subregion and the striatum are responsible for controlling action-based behaviors, like running from a potential marauder. Finally, the extent to which the connections are successful in relaying communication relies on the role of various neurotransmitter systems, such as dopamine and serotonin, thereby resulting in exhibitory and inhibitory behavioral responses (LeDoux, 2007).

[[Image:Amygdalainputs.jpg]]

==Behavior==

In the early 20th century, observed damage in the temporal lobe showed profound changes in behaviors such as fear and sex-related responses (LeDoux, 2007). After determining that the amygdala played a role in these impairments, the inability to account for the underlying substructures of this area resulted in a body of research that was widely misunderstood. It was not until after the discovery of the amygdala’s subcomponents, in which researchers were able to study specific behavioral functions associated with this region (LeDoux, 2007).

'''Fear'''

Fear has been documented throughout scientific literature and more specifically, use of Pavlovian conditioning (the seemingly innate ability to learn stimulus-response (SR) affiliations when presented with associative stimuli) has been shown to consistently and effectively measure such behavior (LeDoux, 2007). The habituation of these associations, through prolonged exposure, implies the developmental aspect of plasticity to aid in the maintenance of short-term memory. Moreover, when these SR associations are re-presented to an individual, the enduring plasticity reveals storage of the appropriate information to the individual’s long-term memory (LeDoux, 2007).

[[Image:Amygdalafear.jpg]]

'''Other'''

While fear response continues to be the most salient behavioral function associated with the amygdala, other research has pointed out that this region is also involved in other emotions such as aggression, sexuality, and addictive, ingestive behaviors (e.g. eating and drinking). Additionally, the amygdala’s ability to release hormones, through neurotransmitter modalities, to other regions of the brain also influences other specific types of cognition, such as attention, perception, and explicit memory (LeDoux, 2007). In other words, the amygdala’s emotional processing to external stimuli establishes connections with other functions of the brain. As earlier noted, the amygdala plays a role in several psychiatric conditions, like autism, schizophrenia, borderline personality disorder, and depression. More importantly, the amygdala is not the cause of these disorders, but rather alterations in the representation of this region result in specific behavioral changes in these individuals (LeDoux, 2007).

'''Relevant Studies'''

Bechara, Tranel, Damasio, Adolphs, Rockland, and Damasio (1995) studied the double dissociation between conditioning and declarative knowledge in relation to the amygdala and the hippocampus in three patients. In two conditioning experiments, using a skin conductance response (SCR) measure, the researchers found that the patient with bilateral damage to the amygdala was unable to acquire the conditioned autonomic responses to the presented visual or auditory stimuli; however, declarative knowledge of the stimuli was largely spared (Bechara et al., 1995). Conversely, the patient with hippocampal damage was able to acquire the conditioned autonomic responses, but failed to retain declarative knowledge of the material. Lastly, the third patient had damage to both brain areas, resulting in an inability to acquire both conditioned autonomic responses and declarative facts. Consistent with previous research, this study further suggested the role the amygdala plays in associative cues of affect, while the hippocampus is responsible for learning the critical relationships among these cues (Bechara et al., 1995).

A later study conducted by Bechara, Damasio, Damasio, and Lee (1999) focused on the contributions of the amygdala and the ventromedial prefrontal (VMF) cortex in human decision-making. Using the “gambling task” to measure decision-making and a skin conductance response (SCR) instrument, the researchers were able to effectively study a group of patients with bilateral amygdala damage and another group with VMF bilateral damage (Bechara et al., 1999). In a Pavlovian conditioning experiment, participants were also tested for acquisition of a conditioned SCR to paired visual stimuli and an aversive loud noise (Bechara et al., 1999). Results of the study revealed that the two areas have distinct influences on decision-making. More specifically, patients with amygdala damage were unable to produce SCRs on both the “gambling task” as well as the conditioning experiment. The group of individuals with VMF damage were also unable to generate SCRs on the “gambling task,” but were able to produce a response when presented with a reward or punishment (e.g. play money), while the amygdala-damaged patients still failed to produce such a response when they received similar reinforcements (Bechara et al., 1999).

The differences associated with decision-making in the two groups implies potentially bigger consequences for the patients with bilateral amygdala damage, in that the failure to evoke the appropriate somatic state results in impairment of future decision-making tasks that elicit similar somatic affects (Bechara, 1999). In sum, this study paralleled earlier research about the underlying functions of the orbitofrontal cortex and the basolateral amygdala and their association with goal-directed behavior. While both groups of patients showed impairments on similar decision-making tasks, the individuals with bilateral damage to the amygdala are much more susceptible to both psychologically and physically harmful real-life situations, where a decision may be critical (Bechara, 1999). In other words, their overall failure to adequately respond to external stimuli due to alterations in emotional states (e.g. fear), may therefore cause such individuals to choose a course of action, in which an unfavorable outcome could result in devastating mental and/or physical consequences.

'''Interesting fact'''

The amygdala is responsible for the emotional reactions to music.

==References==

Bechara, A., Tranel, D., Damasio, H., Adolphs, R., Rockland, C., & Damasio, A. R.
(1995). Double dissociation of conditioning and declarative knowledge relative
to the amygdala and hippocampus in humans. Science, 269, 1115-1118.

Bechara, A., Damasio, H., Damasio, A. R., & Lee, G. P. (1999). Different contributions
of the human amygdala and ventromedial prefrontal cortex to decision-making.
The Journal of Neuroscience, 19(3), 5473-5481.

LeDoux, J. (2007). The amygdala. Current Biology, 17, 868-874.

File:Synesthesia1.gif

Cmcfall — Sun, 27 Apr 2008 22:56:05 GMT

Cmcfall:

File:Wisconsincardsort.jpg

Cmcfall — Sun, 27 Apr 2008 22:55:38 GMT

Cmcfall:

File:Brocasaphasia8.jpg

Cmcfall — Sun, 27 Apr 2008 22:54:28 GMT

Cmcfall:

File:AmygdalaInputs.jpg

Cmcfall — Sun, 27 Apr 2008 22:53:36 GMT

Cmcfall:

Amygdala

Cmcfall — Sun, 27 Apr 2008 22:35:58 GMT

Cmcfall:

[[Category:Brain areas]]

==Overview==

The amygdala represents an anatomical structure of the brain that is involved in a range of behavioral and mental conditions (LeDoux, 2007). Previously, this area had received little scientific recognition, but now it is one of the most extensively studied brain regions. The name “amygdala” is rooted in Greek and refers to the almond-shaped structure located bilaterally within the temporal lobes of the limbic system (LeDoux, 2007). Most individuals assume the amygdala to be comprised of a single mass; however, its composition includes several nuclei, which can be found in species of higher cognitive functioning, including humans and primates. Consistent with this view, it can be argued that the amygdala is not a unitary structure or function, but rather accords several regions that contribute to cognitive functions of other areas in the brain (LeDoux, 2007). In specific, the lateral and basal amygdala are viewed as nuclear extensions of the cortex, while the central and medial nuclei are part of ventral expansions of the striatum and each of these areas can further be divided into subnuclei, which are all relevant to the study of this anatomical region. For example, the dorsal subcomponent of the lateral nucleus is said to be involved in varying aspects of fear memory (LeDoux, 2007).

[[Image:Amygdala-hippocampus.jpg]]

==Connectivity==

The importance of connectivity points to the ability for specific areas of the brain to make connections with other related regions for the purpose of function (LeDoux, 2007). For instance, the lateral amygdala is responsible for receiving stimulatory input from different sensory systems, such as the visual, somatosensory, olfactory, and auditory modalities (LeDoux, 2007). These inputs are then transferred and consummated in the dorsal subnucleus. This subregion then relays information to the ventrolateral and medial areas in order to connect with other areas of the amygdala (LeDoux, 2007).
The region most notable in behavioral and physiological output is the central nucleus, in which connections from the medial subarea and other interconnected nuclei (e.g. basal nucleus) are involved, at least for the expression of emotional responses. As previously mentioned, areas in the striatum also connect with the central nucleus in instrumental behaviors (LeDoux, 2007). More specifically, sensory output from the central amygdala to the brainstem results in the management of emotions, but the interconnectivity between the basal subregion and the striatum are responsible for controlling action-based behaviors, like running from a potential marauder. Finally, the extent to which the connections are successful in relaying communication relies on the role of various neurotransmitter systems, such as dopamine and serotonin, thereby resulting in exhibitory and inhibitory behavioral responses (LeDoux, 2007).

==Behavior==

In the early 20th century, observed damage in the temporal lobe showed profound changes in behaviors such as fear and sex-related responses (LeDoux, 2007). After determining that the amygdala played a role in these impairments, the inability to account for the underlying substructures of this area resulted in a body of research that was widely misunderstood. It was not until after the discovery of the amygdala’s subcomponents, in which researchers were able to study specific behavioral functions associated with this region (LeDoux, 2007).

'''Fear'''

Fear has been documented throughout scientific literature and more specifically, use of Pavlovian conditioning (the seemingly innate ability to learn stimulus-response (SR) affiliations when presented with associative stimuli) has been shown to consistently and effectively measure such behavior (LeDoux, 2007). The habituation of these associations, through prolonged exposure, implies the developmental aspect of plasticity to aid in the maintenance of short-term memory. Moreover, when these SR associations are re-presented to an individual, the enduring plasticity reveals storage of the appropriate information to the individual’s long-term memory (LeDoux, 2007).

[[Image:Amygdalafear.jpg]]

'''Other'''

While fear response continues to be the most salient behavioral function associated with the amygdala, other research has pointed out that this region is also involved in other emotions such as aggression, sexuality, and addictive, ingestive behaviors (e.g. eating and drinking). Additionally, the amygdala’s ability to release hormones, through neurotransmitter modalities, to other regions of the brain also influences other specific types of cognition, such as attention, perception, and explicit memory (LeDoux, 2007). In other words, the amygdala’s emotional processing to external stimuli establishes connections with other functions of the brain. As earlier noted, the amygdala plays a role in several psychiatric conditions, like autism, schizophrenia, borderline personality disorder, and depression. More importantly, the amygdala is not the cause of these disorders, but rather alterations in the representation of this region result in specific behavioral changes in these individuals (LeDoux, 2007).

'''Relevant Studies'''

Bechara, Tranel, Damasio, Adolphs, Rockland, and Damasio (1995) studied the double dissociation between conditioning and declarative knowledge in relation to the amygdala and the hippocampus in three patients. In two conditioning experiments, using a skin conductance response (SCR) measure, the researchers found that the patient with bilateral damage to the amygdala was unable to acquire the conditioned autonomic responses to the presented visual or auditory stimuli; however, declarative knowledge of the stimuli was largely spared (Bechara et al., 1995). Conversely, the patient with hippocampal damage was able to acquire the conditioned autonomic responses, but failed to retain declarative knowledge of the material. Lastly, the third patient had damage to both brain areas, resulting in an inability to acquire both conditioned autonomic responses and declarative facts. Consistent with previous research, this study further suggested the role the amygdala plays in associative cues of affect, while the hippocampus is responsible for learning the critical relationships among these cues (Bechara et al., 1995).

A later study conducted by Bechara, Damasio, Damasio, and Lee (1999) focused on the contributions of the amygdala and the ventromedial prefrontal (VMF) cortex in human decision-making. Using the “gambling task” to measure decision-making and a skin conductance response (SCR) instrument, the researchers were able to effectively study a group of patients with bilateral amygdala damage and another group with VMF bilateral damage (Bechara et al., 1999). In a Pavlovian conditioning experiment, participants were also tested for acquisition of a conditioned SCR to paired visual stimuli and an aversive loud noise (Bechara et al., 1999). Results of the study revealed that the two areas have distinct influences on decision-making. More specifically, patients with amygdala damage were unable to produce SCRs on both the “gambling task” as well as the conditioning experiment. The group of individuals with VMF damage were also unable to generate SCRs on the “gambling task,” but were able to produce a response when presented with a reward or punishment (e.g. play money), while the amygdala-damaged patients still failed to produce such a response when they received similar reinforcements (Bechara et al., 1999).

The differences associated with decision-making in the two groups implies potentially bigger consequences for the patients with bilateral amygdala damage, in that the failure to evoke the appropriate somatic state results in impairment of future decision-making tasks that elicit similar somatic affects (Bechara, 1999). In sum, this study paralleled earlier research about the underlying functions of the orbitofrontal cortex and the basolateral amygdala and their association with goal-directed behavior. While both groups of patients showed impairments on similar decision-making tasks, the individuals with bilateral damage to the amygdala are much more susceptible to both psychologically and physically harmful real-life situations, where a decision may be critical (Bechara, 1999). In other words, their overall failure to adequately respond to external stimuli due to alterations in emotional states (e.g. fear), may therefore cause such individuals to choose a course of action, in which an unfavorable outcome could result in devastating mental and/or physical consequences.

'''Interesting fact'''

The amygdala is responsible for the emotional reactions to music.

==References==

Bechara, A., Tranel, D., Damasio, H., Adolphs, R., Rockland, C., & Damasio, A. R.
(1995). Double dissociation of conditioning and declarative knowledge relative
to the amygdala and hippocampus in humans. Science, 269, 1115-1118.

Bechara, A., Damasio, H., Damasio, A. R., & Lee, G. P. (1999). Different contributions
of the human amygdala and ventromedial prefrontal cortex to decision-making.
The Journal of Neuroscience, 19(3), 5473-5481.

LeDoux, J. (2007). The amygdala. Current Biology, 17, 868-874.

Amygdala

Cmcfall — Sun, 27 Apr 2008 22:34:47 GMT

Cmcfall:

[[Category:Brain areas]]

==Overview==

The amygdala represents an anatomical structure of the brain that is involved in a range of behavioral and mental conditions (LeDoux, 2007). Previously, this area had received little scientific recognition, but now it is one of the most extensively studied brain regions. The name “amygdala” is rooted in Greek and refers to the almond-shaped structure located bilaterally within the temporal lobes of the limbic system (LeDoux, 2007). Most individuals assume the amygdala to be comprised of a single mass; however, its composition includes several nuclei, which can be found in species of higher cognitive functioning, including humans and primates. Consistent with this view, it can be argued that the amygdala is not a unitary structure or function, but rather accords several regions that contribute to cognitive functions of other areas in the brain (LeDoux, 2007). In specific, the lateral and basal amygdala are viewed as nuclear extensions of the cortex, while the central and medial nuclei are part of ventral expansions of the striatum and each of these areas can further be divided into subnuclei, which are all relevant to the study of this anatomical region. For example, the dorsal subcomponent of the lateral nucleus is said to be involved in varying aspects of fear memory (LeDoux, 2007).

[[Image:Amygdala-hippocampus.jpg]]

==Connectivity==

The importance of connectivity points to the ability for specific areas of the brain to make connections with other related regions for the purpose of function (LeDoux, 2007). For instance, the lateral amygdala is responsible for receiving stimulatory input from different sensory systems, such as the visual, somatosensory, olfactory, and auditory modalities (LeDoux, 2007). These inputs are then transferred and consummated in the dorsal subnucleus. This subregion then relays information to the ventrolateral and medial areas in order to connect with other areas of the amygdala (LeDoux, 2007).
The region most notable in behavioral and physiological output is the central nucleus, in which connections from the medial subarea and other interconnected nuclei (e.g. basal nucleus) are involved, at least for the expression of emotional responses. As previously mentioned, areas in the striatum also connect with the central nucleus in instrumental behaviors (LeDoux, 2007). More specifically, sensory output from the central amygdala to the brainstem results in the management of emotions, but the interconnectivity between the basal subregion and the striatum are responsible for controlling action-based behaviors, like running from a potential marauder. Finally, the extent to which the connections are successful in relaying communication relies on the role of various neurotransmitter systems, such as dopamine and serotonin, thereby resulting in exhibitory and inhibitory behavioral responses (LeDoux, 2007).

==Behavior==

In the early 20th century, observed damage in the temporal lobe showed profound changes in behaviors such as fear and sex-related responses (LeDoux, 2007). After determining that the amygdala played a role in these impairments, the inability to account for the underlying substructures of this area resulted in a body of research that was widely misunderstood. It was not until after the discovery of the amygdala’s subcomponents, in which researchers were able to study specific behavioral functions associated with this region (LeDoux, 2007).

'''Fear'''

Fear has been documented throughout scientific literature and more specifically, use of Pavlovian conditioning (the seemingly innate ability to learn stimulus-response (SR) affiliations when presented with associative stimuli) has been shown to consistently and effectively measure such behavior (LeDoux, 2007). The habituation of these associations, through prolonged exposure, implies the developmental aspect of plasticity to aid in the maintenance of short-term memory. Moreover, when these SR associations are re-presented to an individual, the enduring plasticity reveals storage of the appropriate information to the individual’s long-term memory (LeDoux, 2007).

[[Image:Amygdalafear.jpg]]

'''Other'''

While fear response continues to be the most salient behavioral function associated with the amygdala, other research has pointed out that this region is also involved in other emotions such as aggression, sexuality, and addictive, ingestive behaviors (e.g. eating and drinking). Additionally, the amygdala’s ability to release hormones, through neurotransmitter modalities, to other regions of the brain also influences other specific types of cognition, such as attention, perception, and explicit memory (LeDoux, 2007). In other words, the amygdala’s emotional processing to external stimuli establishes connections with other functions of the brain. As earlier noted, the amygdala plays a role in several psychiatric conditions, like autism, schizophrenia, borderline personality disorder, and depression. More importantly, the amygdala is not the cause of these disorders, but rather alterations in the representation of this region result in specific behavioral changes in these individuals (LeDoux, 2007).

'''Relevant Studies'''

Bechara, Tranel, Damasio, Adolphs, Rockland, and Damasio (1995) studied the double dissociation between conditioning and declarative knowledge in relation to the amygdala and the hippocampus in three patients. In two conditioning experiments, using a skin conductance response (SCR) measure, the researchers found that the patient with bilateral damage to the amygdala was unable to acquire the conditioned autonomic responses to the presented visual or auditory stimuli; however, declarative knowledge of the stimuli was largely spared (Bechara et al., 1995). Conversely, the patient with hippocampal damage was able to acquire the conditioned autonomic responses, but failed to retain declarative knowledge of the material. Lastly, the third patient had damage to both brain areas, resulting in an inability to acquire both conditioned autonomic responses and declarative facts. Consistent with previous research, this study further suggested the role the amygdala plays in associative cues of affect, while the hippocampus is responsible for learning the critical relationships among these cues (Bechara et al., 1995).

A later study conducted by Bechara, Damasio, Damasio, and Lee (1999) focused on the contributions of the amygdala and the ventromedial prefrontal (VMF) cortex in human decision-making. Using the “gambling task” to measure decision-making and a skin conductance response (SCR) instrument, the researchers were able to effectively study a group of patients with bilateral amygdala damage and another group with VMF bilateral damage (Bechara et al., 1999). In a Pavlovian conditioning experiment, participants were also tested for acquisition of a conditioned SCR to paired visual stimuli and an aversive loud noise (Bechara et al., 1999). Results of the study revealed that the two areas have distinct influences on decision-making. More specifically, patients with amygdala damage were unable to produce SCRs on both the “gambling task” as well as the conditioning experiment. The group of individuals with VMF damage were also unable to generate SCRs on the “gambling task,” but were able to produce a response when presented with a reward or punishment (e.g. play money), while the amygdala-damaged patients still failed to produce such a response when they received similar reinforcements (Bechara et al., 1999). The differences associated with decision-making in the two groups implies potentially bigger consequences for the patients with bilateral amygdala damage, in that the failure to evoke the appropriate somatic state results in impairment of future decision-making tasks that elicit similar somatic affects (Bechara, 1999). In sum, this study paralleled earlier research about the underlying functions of the orbitofrontal cortex and the basolateral amygdala and their association with goal-directed behavior. While both groups of patients showed impairments on similar decision-making tasks, the individuals with bilateral damage to the amygdala are much more susceptible to both psychologically and physically harmful real-life situations, where a decision may be critical (Bechara, 1999). In other words, their overall failure to adequately respond to external stimuli due to alterations in emotional states (e.g. fear), may therefore cause such individuals to choose a course of action, in which an unfavorable outcome could result in devastating mental and/or physical consequences.

'''Interesting fact'''

The amygdala is responsible for the emotional reactions to music.

==References==

Bechara, A., Tranel, D., Damasio, H., Adolphs, R., Rockland, C., & Damasio, A. R.
(1995). Double dissociation of conditioning and declarative knowledge relative
to the amygdala and hippocampus in humans. Science, 269, 1115-1118.

Bechara, A., Damasio, H., Damasio, A. R., & Lee, G. P. (1999). Different contributions
of the human amygdala and ventromedial prefrontal cortex to decision-making.
The Journal of Neuroscience, 19(3), 5473-5481.

LeDoux, J. (2007). The amygdala. Current Biology, 17, 868-874.

Amygdala

Cmcfall — Sun, 27 Apr 2008 22:34:06 GMT

Cmcfall:

[[Category:Brain areas]]

==Overview==

The amygdala represents an anatomical structure of the brain that is involved in a range of behavioral and mental conditions (LeDoux, 2007). Previously, this area had received little scientific recognition, but now it is one of the most extensively studied brain regions. The name “amygdala” is rooted in Greek and refers to the almond-shaped structure located bilaterally within the temporal lobes of the limbic system (LeDoux, 2007). Most individuals assume the amygdala to be comprised of a single mass; however, its composition includes several nuclei, which can be found in species of higher cognitive functioning, including humans and primates. Consistent with this view, it can be argued that the amygdala is not a unitary structure or function, but rather accords several regions that contribute to cognitive functions of other areas in the brain (LeDoux, 2007). In specific, the lateral and basal amygdala are viewed as nuclear extensions of the cortex, while the central and medial nuclei are part of ventral expansions of the striatum and each of these areas can further be divided into subnuclei, which are all relevant to the study of this anatomical region. For example, the dorsal subcomponent of the lateral nucleus is said to be involved in varying aspects of fear memory (LeDoux, 2007).

[[Image:Amygdala-hippocampus.jpg]]

==Connectivity==

The importance of connectivity points to the ability for specific areas of the brain to make connections with other related regions for the purpose of function (LeDoux, 2007). For instance, the lateral amygdala is responsible for receiving stimulatory input from different sensory systems, such as the visual, somatosensory, olfactory, and auditory modalities (LeDoux, 2007). These inputs are then transferred and consummated in the dorsal subnucleus. This subregion then relays information to the ventrolateral and medial areas in order to connect with other areas of the amygdala (LeDoux, 2007).
The region most notable in behavioral and physiological output is the central nucleus, in which connections from the medial subarea and other interconnected nuclei (e.g. basal nucleus) are involved, at least for the expression of emotional responses. As previously mentioned, areas in the striatum also connect with the central nucleus in instrumental behaviors (LeDoux, 2007). More specifically, sensory output from the central amygdala to the brainstem results in the management of emotions, but the interconnectivity between the basal subregion and the striatum are responsible for controlling action-based behaviors, like running from a potential marauder. Finally, the extent to which the connections are successful in relaying communication relies on the role of various neurotransmitter systems, such as dopamine and serotonin, thereby resulting in exhibitory and inhibitory behavioral responses (LeDoux, 2007).

==Behavior==

In the early 20th century, observed damage in the temporal lobe showed profound changes in behaviors such as fear and sex-related responses (LeDoux, 2007). After determining that the amygdala played a role in these impairments, the inability to account for the underlying substructures of this area resulted in a body of research that was widely misunderstood. It was not until after the discovery of the amygdala’s subcomponents, in which researchers were able to study specific behavioral functions associated with this region (LeDoux, 2007).

'''Fear'''

Fear has been documented throughout scientific literature and more specifically, use of Pavlovian conditioning (the seemingly innate ability to learn stimulus-response (SR) affiliations when presented with associative stimuli) has been shown to consistently and effectively measure such behavior (LeDoux, 2007). The habituation of these associations, through prolonged exposure, implies the developmental aspect of plasticity to aid in the maintenance of short-term memory. Moreover, when these SR associations are re-presented to an individual, the enduring plasticity reveals storage of the appropriate information to the individual’s long-term memory (LeDoux, 2007).

'''Other'''

While fear response continues to be the most salient behavioral function associated with the amygdala, other research has pointed out that this region is also involved in other emotions such as aggression, sexuality, and addictive, ingestive behaviors (e.g. eating and drinking). Additionally, the amygdala’s ability to release hormones, through neurotransmitter modalities, to other regions of the brain also influences other specific types of cognition, such as attention, perception, and explicit memory (LeDoux, 2007). In other words, the amygdala’s emotional processing to external stimuli establishes connections with other functions of the brain. As earlier noted, the amygdala plays a role in several psychiatric conditions, like autism, schizophrenia, borderline personality disorder, and depression. More importantly, the amygdala is not the cause of these disorders, but rather alterations in the representation of this region result in specific behavioral changes in these individuals (LeDoux, 2007).

[[Image:Amygdalafear.jpg]]

'''Relevant Studies'''

Bechara, Tranel, Damasio, Adolphs, Rockland, and Damasio (1995) studied the double dissociation between conditioning and declarative knowledge in relation to the amygdala and the hippocampus in three patients. In two conditioning experiments, using a skin conductance response (SCR) measure, the researchers found that the patient with bilateral damage to the amygdala was unable to acquire the conditioned autonomic responses to the presented visual or auditory stimuli; however, declarative knowledge of the stimuli was largely spared (Bechara et al., 1995). Conversely, the patient with hippocampal damage was able to acquire the conditioned autonomic responses, but failed to retain declarative knowledge of the material. Lastly, the third patient had damage to both brain areas, resulting in an inability to acquire both conditioned autonomic responses and declarative facts. Consistent with previous research, this study further suggested the role the amygdala plays in associative cues of affect, while the hippocampus is responsible for learning the critical relationships among these cues (Bechara et al., 1995).

A later study conducted by Bechara, Damasio, Damasio, and Lee (1999) focused on the contributions of the amygdala and the ventromedial prefrontal (VMF) cortex in human decision-making. Using the “gambling task” to measure decision-making and a skin conductance response (SCR) instrument, the researchers were able to effectively study a group of patients with bilateral amygdala damage and another group with VMF bilateral damage (Bechara et al., 1999). In a Pavlovian conditioning experiment, participants were also tested for acquisition of a conditioned SCR to paired visual stimuli and an aversive loud noise (Bechara et al., 1999). Results of the study revealed that the two areas have distinct influences on decision-making. More specifically, patients with amygdala damage were unable to produce SCRs on both the “gambling task” as well as the conditioning experiment. The group of individuals with VMF damage were also unable to generate SCRs on the “gambling task,” but were able to produce a response when presented with a reward or punishment (e.g. play money), while the amygdala-damaged patients still failed to produce such a response when they received similar reinforcements (Bechara et al., 1999). The differences associated with decision-making in the two groups implies potentially bigger consequences for the patients with bilateral amygdala damage, in that the failure to evoke the appropriate somatic state results in impairment of future decision-making tasks that elicit similar somatic affects (Bechara, 1999). In sum, this study paralleled earlier research about the underlying functions of the orbitofrontal cortex and the basolateral amygdala and their association with goal-directed behavior. While both groups of patients showed impairments on similar decision-making tasks, the individuals with bilateral damage to the amygdala are much more susceptible to both psychologically and physically harmful real-life situations, where a decision may be critical (Bechara, 1999). In other words, their overall failure to adequately respond to external stimuli due to alterations in emotional states (e.g. fear), may therefore cause such individuals to choose a course of action, in which an unfavorable outcome could result in devastating mental and/or physical consequences.

'''Interesting fact'''

The amygdala is responsible for the emotional reactions to music.

==References==

Bechara, A., Tranel, D., Damasio, H., Adolphs, R., Rockland, C., & Damasio, A. R.
(1995). Double dissociation of conditioning and declarative knowledge relative
to the amygdala and hippocampus in humans. Science, 269, 1115-1118.

Bechara, A., Damasio, H., Damasio, A. R., & Lee, G. P. (1999). Different contributions
of the human amygdala and ventromedial prefrontal cortex to decision-making.
The Journal of Neuroscience, 19(3), 5473-5481.

LeDoux, J. (2007). The amygdala. Current Biology, 17, 868-874.

Pascual-Leone et al. (1995)

Cmcfall — Sun, 27 Apr 2008 22:27:18 GMT

Cmcfall:

[[Category:Plasticity Symposium]]

==Introduction==

Pascula-Leone, Wassermann, Sadato, and Hallett (1995) conducted a study to examine the representation of the motor cortical outputs in relation to a preceding activity. This study emphasized the importance of the correlation between precise timing and skill acquisition. More specifically, the current study focused exclusively on six blind participants, who were proficient in reading Braille, which requires the use of the tip of the index finger in order to discriminate between differential patterns of raised dots. The finger is subject to side-to-side movements “at a constant amplitude and speed to enhance this sensory discrimination by the pressure receptors in the skin” (Pascula-Leone et al., 1995). In previous studies, it has been found that the sensorimotor representation of the reading finger is enlarged in these blind, proficient Braille readers when compared to the same finger of the opposite hand, or with either finger in normal, sighted individuals.

The extent to which this modulation is enlarged would very well question the size and stability of these cortical representations, for it seems unlikely that such an enlargement would inhibit a proficient Braille reader from the use of his/her other fingers. This dilemma has led to the hypothesis that if this transformation in the motor cortical output is taking place during skill acquisition that requires the use of a specific body part, it should also be expected to reduce to a baseline after learning of the relevant task has occurred. Thus, the cortical representation gives rise to a dynamic, flexible system, whose activation is dependent upon the previous activity (Pascula-Leone et al., 1995). The flexibility of this system led the researchers in the current study to further investigate the stability as well as the size of this motor cortical output representation in proficient Braille readers.

[[Image:Braillealphabet.jpg]]
*'''''The Braille Alphabet'''''

==Method==

Six proficient Braille readers (four men and two women), with ages ranging from 44 to 57 years, participated in this study. These participants were all completely blind before the age of ten, learned to read Braille before the age of 13, and all used the right index finger for character recognition and the left index for line spacing. The experiment tested participants on two different Mondays, which were separated by one week. All Braille readers were tested two times per days (once in the morning and once in the evening). It should be noted that one of the days, in which the participant was tested, was considered to be a “work day,” where he/she read Braille for four to six hours. In contrast, the participants were required to request one of the two testing days off from work without notifying the experimenter, in which they read no Braille. This date was referred to as the “control day” and used as a means of comparison in statistical procedures following the experiment. Using the focal Transcranial Magnetic Stimulation (TMS), this instrument mapped the motor cortical outputs to the left first dorsal interosseous (FDI) as well as the right abductor digiti minimi (ADM) muscles (Pascula-Leone et al., 1995). Additionally, electrodes were connected to the participant’s finger muscles to evaluate the extent to which the brain areas connected to this cortical modulation were enlarged.

==Results==

The findings of the current study support the aforementioned hypothesis that the motor cortical representation is comprised of a dynamic and flexible system, whose organization is largely dependent upon the previous, relevant task. In other words, the current experiment was able to show significant changes in the motor cortical outputs that rapidly adjust to meet the demands and successful completion of the required task.

==Discussion==

This study highlights the developmental characteristic of plasticity in the brain. It shows that this phenomenon is ongoing and not limited to brain damaged individuals. For instance, skill acquisition requires the growth of new neurons that adapt to the relevant task. A case study reported in the article discussed a 54-year-old female, who was blind from birth, due to a rare eye condition called Retrolental Fibroplasia. This disease is most salient in infants and usually results from high concentrations of oxygen, which causes abnormal growth of the fibrous tissue behind the lens to take place (Pascula-Leone et al., 1995). Like the participants in the experimental design, she, too, was a proficient Braille reader, who showed an enlarged motor cortical representation of the right, reading hand (FDI) in contrast to that of her left FDI. After a period of nine months, this subject was tested again, and results from this experiment showed a significant reduction in the cortical output map of the right FDI. Stunned by this finding, researchers were notified of the participant’s recent vacation, in which she did not engage in any Braille reading. Consequently, she was asked to return to the laboratory at the end of work week and surprisingly, they found a “return” to the enlargement of the motor cortical output map that was documented in the first experiment.

Based on this reported case study, along with the findings of the current experiment, it can be concluded that skill acquisition relies on plastic changes in the neural network that must adapt to the demands of the new task. Proficiency in learning may very well rely on a rapid modulation of the cortical representation, which gives rises to a correlation between precision of time and skill acquisition. However, the development of this capacity has also been shown to consist of intracortical connections that become latent due to lack of exposure and practice of the relevant skill. Additionally, a point should be made about this latency, for on the days that did not involve Braille reading, these participants were still most likely engaging in tasks that required the use of similar body parts, and thus the motor cortical outputs were adjusted for these activities. This finding gives rise to the plastic component of the brain, in that the “rewiring” of this neural network results in a failure to rapidly respond after prolonged exposure to a task that requires the use of the same body parts (Pascula-Leone et al., 1995). While this study certainly highlights the underlying neural mechanisms of the plasticity phenomenon, studies involving non-proficient Braille readers should be investigated to assess the types of neural changes that take place following similarly delayed exposure to training.

==References==

Pascual-Leone, A., Wassermann, E. M., Sadato, N., Hallett, M. (1995). The role of reading activity on the modulation of motor cortical outputs to the reading hand in braille readers. Annals of Neurology, 38, 910- 915.

Pascual-Leone et al. (1995)

Cmcfall — Sun, 27 Apr 2008 22:25:10 GMT

Cmcfall:

[[Category:Plasticity Symposium]]

==Introduction==

Pascula-Leone, Wassermann, Sadato, and Hallett (1995) conducted a study to examine the representation of the motor cortical outputs in relation to a preceding activity. This study emphasized the importance of the correlation between precise timing and skill acquisition. More specifically, the current study focused exclusively on six blind participants, who were proficient in reading Braille, which requires the use of the tip of the index finger in order to discriminate between differential patterns of raised dots. The finger is subject to side-to-side movements “at a constant amplitude and speed to enhance this sensory discrimination by the pressure receptors in the skin” (Pascula-Leone et. al., 1995). In previous studies, it has been found that the sensorimotor representation of the reading finger is enlarged in these blind, proficient Braille readers when compared to the same finger of the opposite hand, or with either finger in normal, sighted individuals. The extent to which this modulation is enlarged would very well question the size and stability of these cortical representations, for it seems unlikely that such an enlargement would inhibit a proficient Braille reader from the use of his/her other fingers. This dilemma has led to the hypothesis that if this transformation in the motor cortical output is taking place during skill acquisition that requires the use of a specific body part, it should also be expected to reduce to a baseline after learning of the relevant task has occurred. Thus, the cortical representation gives rise to a dynamic, flexible system, whose activation is dependent upon the previous activity (Pascula-Leone et. al., 1995). The flexibility of this system led the researchers in the current study to further investigate the stability as well as the size of this motor cortical output representation in proficient Braille readers.

[[Image:Braillealphabet.jpg]]
*'''''The Braille Alphabet'''''

==Method==

Six proficient Braille readers (four men and two women), with ages ranging from 44 to 57 years, participated in this study. These participants were all completely blind before the age of ten, learned to read Braille before the age of 13, and all used the right index finger for character recognition and the left index for line spacing. The experiment tested participants on two different Mondays, which were separated by one week. All Braille readers were tested two times per days (once in the morning and once in the evening). It should be noted that one of the days, in which the participant was tested, was considered to be a “work day,” where he/she read Braille for four to six hours. In contrast, the participants were required to request one of the two testing days off from work without notifying the experimenter, in which they read no Braille. This date was referred to as the “control day” and used as a means of comparison in statistical procedures following the experiment. Using the focal Transcranial Magnetic Stimulation (TMS), this instrument mapped the motor cortical outputs to the left first dorsal interosseous (FDI) as well as the right abductor digiti minimi (ADM) muscles (Pascula-Leone et. al., 1995). Additionally, electrodes were connected to the participant’s finger muscles to evaluate the extent to which the brain areas connected to this cortical modulation were enlarged.

==Results==

The findings of the current study support the aforementioned hypothesis that the motor cortical representation is comprised of a dynamic and flexible system, whose organization is largely dependent upon the previous, relevant task. In other words, the current experiment was able to show significant changes in the motor cortical outputs that rapidly adjust to meet the demands and successful completion of the required task.

==Discussion==

This study highlights the developmental characteristic of plasticity in the brain. It shows that this phenomenon is ongoing and not limited to brain damaged individuals. For instance, skill acquisition requires the growth of new neurons that adapt to the relevant task. A case study reported in the article discussed a 54-year-old female, who was blind from birth, due to a rare eye condition called Retrolental Fibroplasia. This disease is most salient in infants and usually results from high concentrations of oxygen, which causes abnormal growth of the fibrous tissue behind the lens to take place (Pascula-Leone et. al., 1995). Like the participants in the experimental design, she, too, was a proficient Braille reader, who showed an enlarged motor cortical representation of the right, reading hand (FDI) in contrast to that of her left FDI. After a period of nine months, this subject was tested again, and results from this experiment showed a significant reduction in the cortical output map of the right FDI. Stunned by this finding, researchers were notified of the participant’s recent vacation, in which she did not engage in any Braille reading. Consequently, she was asked to return to the laboratory at the end of work week and surprisingly, they found a “return” to the enlargement of the motor cortical output map that was documented in the first experiment. Based on this reported case study, along with the findings of the current experiment, it can be concluded that skill acquisition relies on plastic changes in the neural network that must adapt to the demands of the new task. Proficiency in learning may very well rely on a rapid modulation of the cortical representation, which gives rises to a correlation between precision of time and skill acquisition. However, the development of this capacity has also been shown to consist of intracortical connections that become latent due to lack of exposure and practice of the relevant skill. Additionally, a point should be made about this latency, for on the days that did not involve Braille reading, these participants were still most likely engaging in tasks that required the use of similar body parts, and thus the motor cortical outputs were adjusted for these activities. This finding gives rise to the plastic component of the brain, in that the “rewiring” of this neural network results in a failure to rapidly respond after prolonged exposure to a task that requires the use of the same body parts (Pascula-Leone et. al., 1995). While this study certainly highlights the underlying neural mechanisms of the plasticity phenomenon, studies involving non-proficient Braille readers should be investigated to assess the types of neural changes that take place following similarly delayed exposure to training.

==References==

Pascual-Leone, A., Wassermann, E. M., Sadato, N., Hallett, M. (1995). The role of reading activity on the modulation of motor cortical outputs to the reading hand in braille readers. Annals of Neurology, 38, 910- 915.

Halstead-Reitan battery

Cmcfall — Sun, 27 Apr 2008 22:22:05 GMT

Cmcfall:

[[Category:Neuropsychological methods]]

==Introduction==

Poor performance on tests of neuropsychological assessment indicates either localized or widespread brain damage in an individual (Stirling, 24). Such tests provide the advantage of comparing a patient's test scores to standardized scores by other respondents. In addition, these scores show changes in cognition that may relate to progression of an illness or recovery after an injury (Stirling, 24). To test for these impairments or advances, a series of tests is usually administered and often referred to as a test battery. The Halstead-Reitan Battery (HRB) is the most commonly used and evaluates 'measures of verbal and nonverbal intelligence, language, tactile and manipulative skills, auditory sensitivity, and so on' (Stirling, 24).

==History and Development==

Dr. Ward Halstead and Dr. Ralph Reitan were responsible for the development of the HRB. As early as the 1930s, Dr. Halstead's use of research techniques enabled the accurate identification of localized lesions in the brain (Parsons, 156). During this time, a more holistic approach to neuropsychological assessment was taken, in that brain damage was thought to be more global, rather than attributable to impairments in specific cognitive functions and domains. At the University of Chicago, Ralph Reitan, was one of Halstead's doctoral students and later went on to publish an article, in which a study of 50 individuals proved to quantitatively separate nearly all of the brain-damaged participants from their age/sex matched controls, thereby confirming the validity of Halstead's initial findings (Parsons, 156).

At the time of this discovery, inferences about localized lesions came largely from the realms of neurology and neurosurgery, thus questioning the reliability of this battery as well as the ability to generalize the findings to other populations, including patients in psychiatry (Parsons, 157). Later, Dr. Reitan began to move beyond his original cases and extended his results to other participants and again was able to make accurate predictions about 'the lateralization, localization, and the nature of the disorder itself' (Parsons, 157). The growth and the development of the HRB continues to receive recognition throughout the scientific community and has gradually become the most widespread battery.

==Tests Administered==

Any interpretation of the results from the HRB should consider the variables of age, education, and sex, as well any indication of peripheral injuries. Additionally, hand and eye preference should also be documented, for these inclinations provide important implications in reference to laterality (Parsons, 163). Emotional reactions, attitudes, and any other limitations of the patient should be noted (i.e. a patient's drug administration), which may profoundly impact the interpretation of the results. An accurate interpretation of the test scores relies on a trained psychologist or a professional examiner due to its complex nature. This costly battery takes between five and six hours and requires patience and stamina from both the examiner and patient (Loring & Meador, 1995). The following measures most commonly assessed in neuropsychological evaluations are summarized. (*'''Note''': the tests highlighted in '''bold''' indicate in-class administration and brief instructions are provided).

'''''General Intelligence and Achievement'''''

The general level of functioning is assessed using the Wechsler Adult Intelligence Scale-Revised (WAIS-R), where full scale, verbal, and performance IQs are reported. Also, the Wide Range Achievement Test (WRAT) scores on subtests of reading, spelling, and arithmetic indicate a participant's current level of performance (Parsons, 169).

'''''Sensory-Perceptual and Sensory-Motor Functioning'''''

To test for sensory-perceptual ability, Finger agnosia and impairments in finger tip writing recognition recordings provide important data for the visual, auditory, and tactile modalities (Parsons, 169). Sensory-Motor functioning is measured using the Finger Tapping test, the Purdue or Grooved Pegboard tests, or Grip Strength tests, which provide implications for data involving questions of lateralization and localization. Also, the '''Tactual Performance Test (TPT)''' requires an individual to place shapes in a board while being blindfolded. Following completion of this task, the patient is often asked to draw an illustration of the board from memory (St. John, 2008). Left or ride side deficits give insight about lateralization, whereas any suppressive impulses highlight widespread functionary impairments, instead of specific, or localized brain deficits (Parsons, 169).

'''''Attention, Concentration, and Memory'''''

The importance of these tests lies in their ability to detect brain dysfunction, including laterality. The Wechsler Memory Scale (WMS) or its revised version (WMS-R) is the most common subtest that is used to assess memory. The most prevalent subtests of this Scale include measures of Logical Memory, Visual Reproduction, and Paired Associate Learning (Loring & Meador, 1995). Despite the limitations, which refer to the inability to provide adequate normative data, it is still the most common measure administered.

The Memory Assessment Scales is another collaboration of subtests, although it is less popular and differs in content than those items provided on the WMS. However, it is still sufficient in detecting lateralized dysfunction in candidates for anterior temporal lobectomy. Overall, the Memory Assessment Scales is a series of tests quite similar to those administered for the WMS, but also provides a general memory measure as well as verbal and visual memory subtest scores (Loring & Meador, 1995).

The '''Trial making test''' and the '''Digit Span''' are measures that show sensitivity to attentional impairments. The '''Trial making test''' requires an individual to first make connections between a series of numbers, which is referred to as Trial A. For patients with frontal damage, Trial B is more sensitive, in that the individual is now asked to connect letters with a series of numbers (e.g. A to 1, B to 2, C to 3) and this switching of tasks now demands the use of a different set of 'thinking' skills (St. John, 2008). This transition has proven to be challenging for such patients. The '''Digit Span''' includes a series of tasks that are auditorily presented to the individual. Starting with a smaller set of randomly arranged numbers, these series are to be verbally repeated back in the original or reverse order to the experimenter. The set of numbers increases with each trial and subsequent lines do not use similar arrangements of numbers as the previous tasks (St. John, 2008).

'''''Executive/ Frontal Functions'''''

The Category Test, the '''Trial making test''', and the '''Wisconsin Carding Sorting Test (WCST)''' provide accurate measures of executive or frontal lobe functioning. The '''WCST''' presents the patient with a deck of cards that are to be categorized (e.g. shape, color, number, etc), which is predetermined by the experimenter without the participant's knowledge of this choosing. As the cards are shown to the individual, he/she is required to guess which sorting principle the experimenter has chosen. After clear indication of the participant's discovery of the category, the sorting principle is changed without notifying the individual. Scores are based on the number of errors the participant makes in guessing which sorting principle is being used. Poor performance on such a task implies the failure to inhibit a motor program, a deficit termed ''perseverance'' (St. John, 2008).

'''''Language and Communication Skills'''''

The Reading and Spelling tests from the WRAT, the Aphasia Screening Test, as well as the Vocabulary subtest from the WAIS, provided with a patient's educational background, are all used to measure language skills and possible impairments (Loring & Meador, 1995). Additionally, a patientâ��s nontest related verbal communicative skills (e.g. word finding difficulties) could provide very informative data in predicting relevant dysfunctions (Parsons, 170). For instance, the '''Controlled Oral Word Association''' allows the patient 60 seconds to name as many words as possible beginning with a chosen letter (e.g. 'C'). The second and third trials are conducted in the same manner, but two different letters are selected based on the reported difficulty to retrieve words that begin with those letters (e.g. 'F' and 'L'). An average of 15 words produced is sufficient in normal patients; however, the increasing difficulty of subsequent word associations results in an expected reduction of responses for patients with language and communication deficits (St. John, 2008).

'''''Calculational Skills'''''

On the Arithmetic subtest of the WAIS-R, the patient is required to retain information via memory when problems are presented to him/her orally. Conversely, the WRAT arithmetic allows the patient to use pencil and paper as a means of calculating problems that are presented visually (Parsons, 171). Difficulties with the use of symbols provide evidence of left-hemisphere lesions, whereas visual-spatial deficits predict right-hemisphere lesions. Finally, the Aphasia Screening Test presents two mathematical problems; one presented auditorily and the other requiring the participant to copy a problem and then solve it (Parsons, 171).

'''''Spatial Relationships'''''

Subtests of the WAIS-R including the '''Block Design''' test and '''Rey-Osterreith Complex Figure''' test are the most commonly administered assessments of visual spatial aptitude. The '''Block Design''' test presents an individual with a set of blocks that are to be arranged based upon a predetermined pattern. Scores are based on the amount of time it takes the participant to successfully recreate the design (St. John, 2008). The '''Rey-Osterreith Complex Figure''' test varies in instructional administration, with the participant being asked to draw the complex figure from memory, as a copy, or by section. Other times, the novel way in which the figure is reproduced can sometimes be of interest for researchers (St. John, 2008). Additional administrations of spatial ability may include the Bender Gestalt test; however, it has limitations of poor standardization and scoring criteria and is frequently used to evaluate visual motor functioning (Loring & Meador, 1995). Finally, the Visual Retention Test, Judgement of Line Orientation and Facial Recognition Tests (e.g. Benton and Hooper Visual Organization Test) are also commonly used tests to measure spatial aptitude (Loring & Meador, 1995).

'''''Learning'''''

General information from the WAIS-R is used as a means of providing data on a patient's ability to obtain information from his/her environment and to remember it. High scores on this measure predict pre-morbid attainment, whereas low scores indicate 'lack of attainment, learning disabilities as a child, poor educational opportunities, and brain dysfunction effects on memory and communication' (Parsons, 172). The WMS also provides paired associates of learning both new/difficult as well as old/easy paired associates, particularly in elderly patients, where dementia is suspected. The WAIS Digit-Symbol test, improvement or lack of on the Luria words, and scores on the '''Tactual Performance Test (TPT)''' also reflect issues of learning, particularly the ability to retain new information (Parsons, 172).

'''''Abstracting'''''

Performance on the WAIS that refers to verbal abstracting ability is able to predict left-hemisphere or generalized brain dysfunction. The Category Test, in which a stimulus set is given to the participant and then required to organize it by obeying a set of rules, is used as a measure of nonverbal abstracting aptitude. This task has proven to be particularly sensitive to all types of brain dysfunctions (Parsons, 172).

'''''Problem Solving'''''

The '''TPT''' test is commonly used to measure problem-solving skills, which assesses the patient's strategy usage and approaches to solving problems. The Category test, the '''Block Design''' Test, and the '''Trial making test''' are other instruments that test for problem solving as well as set flexibility and perseverance. These tests coupled with the Digit Symbol Test and the '''TPT''' test reveal that most sensitivity to brain damages and aging in patients (Parsons, 173).

'''''Personality'''''

The Minnesota Multiphasic Personality Inventory (MMPI) provides useful information in diagnosis and treatment. However, this test, along with others, is inadequate in determining whether depressive scores are the cause or the reaction to brain injury (Parsons, 173). While personality tests are not always employed, they are often administered more times than not, particularly to evaluate if personality characteristics are significant factors, and more specifically in patients who report back pain prior to or following back surgery (Loring & Meador, 1995). Overall, personality tests are used as a means of assessing which treatment approach will produce the most effective results (Parsons, 173).

==Limitations==

The original norms for the Halstead tests are based on a relatively small and young sample, resulting in diagnostic issues and potential faulty conclusions (Lezak, 710). However, age-graded norms are now available for means of comparison that include gender and education variables. Also, these tests have been questioned in the elderly population, as they have been shown to be too lengthy and challenging for these individuals (Lezak, 710). Thus, Halstead's core scores have not been included in batteries that evaluate such patients. Nevertheless, the HRB's accuracy and validity still relies on its ability to predict the nature, the presence, as well as the site of a lesion by employing statistical relationships between test scores (Lezak, 710).

==Neuropsychological Findings==

Interpretations of the HRB have proven to be highly accurate in correct predictions. However, the battery has been questioned for its lengthy administration and lack of diagnostic efficiency (Loring & Meador, 1995). While, the mere length of the HRB has shown to be less appropriate for patients in whom attentional issues are present, its most significant contribution comes from its ability to address a variety of behaviors in relation to neuropsychological functioning (Lezak, 712). Variations of the HRB have been used in studies in an effort to indicate more specific brain dysfunctions, for they provide greater sensitivity to test performance of patients (Lezak, 713). More plainly stated, specific tests are selected to test for particular hypotheses about an individual (Stirling, 25). Overall, batteries provide information about changes in cognitive functioning that are helpful for diagnostic purposes, but more importantly, in the efficacy of treatment and recovery.

==References==

Lezak, M. D. (1995). Batteries for assessment of brain damage. In, Neuropsychological assessment (3rd ed., pp. 686-735). New York: Oxford University Press.

Loring, D. W., & Meador, K. J. (1995, May 12). Neuropsychology for neurologists.
Paper presented at the Annual Meeting of the American Academy of Neurology,
Seattle, Washington. Retrieved April 24, 2008, from http://www.nldontheweb.org
/loring-meador.htm

Parsons, O. A. (1986). Overview of the halsted-reitan battery. In T. Incagnoli, G.
Goldstein, & C. J. Golden (Eds.), Clinical application of neuropsychological
test batteries (pp. 155-192). New York and London: Plenum Press.

Stirling, J. (2002). Introducing neuropsychology. New York, NY: Psychology Press.

St. John, S. (2008). Neuropsychological tests. Retrieved April 24, 2008, from Rollins
College, Blackboard Web site: http://blackboard.rollins.edu/webapps/portal/
frameset.jsp?tab=course&url=bin/common/course.pl?course_id=5963_1

Halstead-Reitan battery

Cmcfall — Sun, 27 Apr 2008 22:20:04 GMT

Cmcfall:

[[Category:Neuropsychological methods]]

==Introduction==

Poor performance on tests of neuropsychological assessment indicates either localized or widespread brain damage in an individual (Stirling, 24). Such tests provide the advantage of comparing a patient's test scores to standardized scores by other respondents. In addition, these scores show changes in cognition that may relate to progression of an illness or recovery after an injury (Stirling, 24). To test for these impairments or advances, a series of tests is usually administered and often referred to as a test battery. The Halstead-Reitan Battery (HRB) is the most commonly used and evaluates 'measures of verbal and nonverbal intelligence, language, tactile and manipulative skills, auditory sensitivity, and so on' (Stirling, 24).

==History and Development==

Dr. Ward Halstead and Dr. Ralph Reitan were responsible for the development of the HRB. As early as the 1930s, Dr. Halstead's use of research techniques enabled the accurate identification of localized lesions in the brain (Parsons, 156). During this time, a more holistic approach to neuropsychological assessment was taken, in that brain damage was thought to be more global, rather than attributable to impairments in specific cognitive functions and domains. At the University of Chicago, Ralph Reitan, was one of Halstead's doctoral students and later went on to publish an article, in which a study of 50 individuals proved to quantitatively separate nearly all of the brain-damaged participants from their age/sex matched controls, thereby confirming the validity of Halstead's initial findings (Parsons, 156).

At the time of this discovery, inferences about localized lesions came largely from the realms of neurology and neurosurgery, thus questioning the reliability of this battery as well as the ability to generalize the findings to other populations, including patients in psychiatry (Parsons, 157). Later, Dr. Reitan began to move beyond his original cases and extended his results to other participants and again was able to make accurate predictions about 'the lateralization, localization, and the nature of the disorder itself' (Parsons, 157). The growth and the development of the HRB continues to receive recognition throughout the scientific community and has gradually become the most widespread battery.

==Tests Administered==

Any interpretation of the results from the HRB should consider the variables of age, education, and sex, as well any indication of peripheral injuries. Additionally, hand and eye preference should also be documented, for these inclinations provide important implications in reference to laterality (Parsons, 163). Emotional reactions, attitudes, and any other limitations of the patient should be noted (i.e. a patient's drug administration), which may profoundly impact the interpretation of the results. An accurate interpretation of the test scores relies on a trained psychologist or a professional examiner due to its complex nature. This costly battery takes between five and six hours and requires patience and stamina from both the examiner and patient (Loring & Meador, 1995). The following measures most commonly assessed in neuropsychological evaluations are summarized. (*'''Note''': the tests highlighted in '''bold''' indicate in-class administration and brief instructions are provided).

'''General Intelligence and Achievement'''

The general level of functioning is assessed using the Wechsler Adult Intelligence Scale-Revised (WAIS-R), where full scale, verbal, and performance IQs are reported. Also, the Wide Range Achievement Test (WRAT) scores on subtests of reading, spelling, and arithmetic indicate a participant's current level of performance (Parsons, 169).

'''Sensory-Perceptual and Sensory-Motor Functioning'''

To test for sensory-perceptual ability, Finger agnosia and impairments in finger tip writing recognition recordings provide important data for the visual, auditory, and tactile modalities (Parsons, 169). Sensory-Motor functioning is measured using the Finger Tapping test, the Purdue or Grooved Pegboard tests, or Grip Strength tests, which provide implications for data involving questions of lateralization and localization. Also, the '''Tactual Performance Test (TPT)''' requires an individual to place shapes in a board while being blindfolded. Following completion of this task, the patient is often asked to draw an illustration of the board from memory (St. John, 2008). Left or ride side deficits give insight about lateralization, whereas any suppressive impulses highlight widespread functionary impairments, instead of specific, or localized brain deficits (Parsons, 169).

'''Attention, Concentration, and Memory'''

The importance of these tests lies in their ability to detect brain dysfunction, including laterality. The Wechsler Memory Scale (WMS) or its revised version (WMS-R) is the most common subtest that is used to assess memory. The most prevalent subtests of this Scale include measures of Logical Memory, Visual Reproduction, and Paired Associate Learning (Loring & Meador, 1995). Despite the limitations, which refer to the inability to provide adequate normative data, it is still the most common measure administered.

The Memory Assessment Scales is another collaboration of subtests, although it is less popular and differs in content than those items provided on the WMS. However, it is still sufficient in detecting lateralized dysfunction in candidates for anterior temporal lobectomy. Overall, the Memory Assessment Scales is a series of tests quite similar to those administered for the WMS, but also provides a general memory measure as well as verbal and visual memory subtest scores (Loring & Meador, 1995).

The '''Trial making test''' and the '''Digit Span''' are measures that show sensitivity to attentional impairments. The '''Trial making test''' requires an individual to first make connections between a series of numbers, which is referred to as Trial A. For patients with frontal damage, Trial B is more sensitive, in that the individual is now asked to connect letters with a series of numbers (e.g. A to 1, B to 2, C to 3) and this switching of tasks now demands the use of a different set of 'thinking' skills (St. John, 2008). This transition has proven to be challenging for such patients. The '''Digit Span''' includes a series of tasks that are auditorily presented to the individual. Starting with a smaller set of randomly arranged numbers, these series are to be verbally repeated back in the original or reverse order to the experimenter. The set of numbers increases with each trial and subsequent lines do not use similar arrangements of numbers as the previous tasks (St. John, 2008).

'''Executive/ Frontal Functions'''

The Category Test, the '''Trial making test''', and the '''Wisconsin Carding Sorting Test (WCST)''' provide accurate measures of executive or frontal lobe functioning. The '''WCST''' presents the patient with a deck of cards that are to be categorized (e.g. shape, color, number, etc), which is predetermined by the experimenter without the participant's knowledge of this choosing. As the cards are shown to the individual, he/she is required to guess which sorting principle the experimenter has chosen. After clear indication of the participant's discovery of the category, the sorting principle is changed without notifying the individual. Scores are based on the number of errors the participant makes in guessing which sorting principle is being used. Poor performance on such a task implies the failure to inhibit a motor program, a deficit termed ''perseverance'' (St. John, 2008).

'''Language and Communication Skills'''

The Reading and Spelling tests from the WRAT, the Aphasia Screening Test, as well as the Vocabulary subtest from the WAIS, provided with a patient's educational background, are all used to measure language skills and possible impairments (Loring & Meador, 1995). Additionally, a patientâ��s nontest related verbal communicative skills (e.g. word finding difficulties) could provide very informative data in predicting relevant dysfunctions (Parsons, 170). For instance, the '''Controlled Oral Word Association''' allows the patient 60 seconds to name as many words as possible beginning with a chosen letter (e.g. 'C'). The second and third trials are conducted in the same manner, but two different letters are selected based on the reported difficulty to retrieve words that begin with those letters (e.g. 'F' and 'L'). An average of 15 words produced is sufficient in normal patients; however, the increasing difficulty of subsequent word associations results in an expected reduction of responses for patients with language and communication deficits (St. John, 2008).

'''Calculational Skills'''

On the Arithmetic subtest of the WAIS-R, the patient is required to retain information via memory when problems are presented to him/her orally. Conversely, the WRAT arithmetic allows the patient to use pencil and paper as a means of calculating problems that are presented visually (Parsons, 171). Difficulties with the use of symbols provide evidence of left-hemisphere lesions, whereas visual-spatial deficits predict right-hemisphere lesions. Finally, the Aphasia Screening Test presents two mathematical problems; one presented auditorily and the other requiring the participant to copy a problem and then solve it (Parsons, 171).

'''Spatial Relationships'''

Subtests of the WAIS-R including the '''Block Design''' test and '''Rey-Osterreith Complex Figure''' test are the most commonly administered assessments of visual spatial aptitude. The '''Block Design''' test presents an individual with a set of blocks that are to be arranged based upon a predetermined pattern. Scores are based on the amount of time it takes the participant to successfully recreate the design (St. John, 2008). The '''Rey-Osterreith Complex Figure''' test varies in instructional administration, with the participant being asked to draw the complex figure from memory, as a copy, or by section. Other times, the novel way in which the figure is reproduced can sometimes be of interest for researchers (St. John, 2008). Additional administrations of spatial ability may include the Bender Gestalt test; however, it has limitations of poor standardization and scoring criteria and is frequently used to evaluate visual motor functioning (Loring & Meador, 1995). Finally, the Visual Retention Test, Judgement of Line Orientation and Facial Recognition Tests (e.g. Benton and Hooper Visual Organization Test) are also commonly used tests to measure spatial aptitude (Loring & Meador, 1995).

'''Learning'''

General information from the WAIS-R is used as a means of providing data on a patient's ability to obtain information from his/her environment and to remember it. High scores on this measure predict pre-morbid attainment, whereas low scores indicate 'lack of attainment, learning disabilities as a child, poor educational opportunities, and brain dysfunction effects on memory and communication' (Parsons, 172). The WMS also provides paired associates of learning both new/difficult as well as old/easy paired associates, particularly in elderly patients, where dementia is suspected. The WAIS Digit-Symbol test, improvement or lack of on the Luria words, and scores on the '''Tactual Performance Test (TPT)''' also reflect issues of learning, particularly the ability to retain new information (Parsons, 172).

'''Abstracting'''

Performance on the WAIS that refers to verbal abstracting ability is able to predict left-hemisphere or generalized brain dysfunction. The Category Test, in which a stimulus set is given to the participant and then required to organize it by obeying a set of rules, is used as a measure of nonverbal abstracting aptitude. This task has proven to be particularly sensitive to all types of brain dysfunctions (Parsons, 172).

'''Problem Solving'''

The '''TPT''' test is commonly used to measure problem-solving skills, which assesses the patient's strategy usage and approaches to solving problems. The Category test, the '''Block Design''' Test, and the '''Trial making test''' are other instruments that test for problem solving as well as set flexibility and perseverance. These tests coupled with the Digit Symbol Test and the '''TPT''' test reveal that most sensitivity to brain damages and aging in patients (Parsons, 173).

'''Personality'''

The Minnesota Multiphasic Personality Inventory (MMPI) provides useful information in diagnosis and treatment. However, this test, along with others, is inadequate in determining whether depressive scores are the cause or the reaction to brain injury (Parsons, 173). While personality tests are not always employed, they are often administered more times than not, particularly to evaluate if personality characteristics are significant factors, and more specifically in patients who report back pain prior to or following back surgery (Loring & Meador, 1995). Overall, personality tests are used as a means of assessing which treatment approach will produce the most effective results (Parsons, 173).

==Limitations==

The original norms for the Halstead tests are based on a relatively small and young sample, resulting in diagnostic issues and potential faulty conclusions (Lezak, 710). However, age-graded norms are now available for means of comparison that include gender and education variables. Also, these tests have been questioned in the elderly population, as they have been shown to be too lengthy and challenging for these individuals (Lezak, 710). Thus, Halstead's core scores have not been included in batteries that evaluate such patients. Nevertheless, the HRB's accuracy and validity still relies on its ability to predict the nature, the presence, as well as the site of a lesion by employing statistical relationships between test scores (Lezak, 710).

==Neuropsychological Findings==

Interpretations of the HRB have proven to be highly accurate in correct predictions. However, the battery has been questioned for its lengthy administration and lack of diagnostic efficiency (Loring & Meador, 1995). While, the mere length of the HRB has shown to be less appropriate for patients in whom attentional issues are present, its most significant contribution comes from its ability to address a variety of behaviors in relation to neuropsychological functioning (Lezak, 712). Variations of the HRB have been used in studies in an effort to indicate more specific brain dysfunctions, for they provide greater sensitivity to test performance of patients (Lezak, 713). More plainly stated, specific tests are selected to test for particular hypotheses about an individual (Stirling, 25). Overall, batteries provide information about changes in cognitive functioning that are helpful for diagnostic purposes, but more importantly, in the efficacy of treatment and recovery.

==References==

Lezak, M. D. (1995). Batteries for assessment of brain damage. In, Neuropsychological assessment (3rd ed., pp. 686-735). New York: Oxford University Press.

Loring, D. W., & Meador, K. J. (1995, May 12). Neuropsychology for neurologists.
Paper presented at the Annual Meeting of the American Academy of Neurology,
Seattle, Washington. Retrieved April 24, 2008, from http://www.nldontheweb.org
/loring-meador.htm

Parsons, O. A. (1986). Overview of the halsted-reitan battery. In T. Incagnoli, G.
Goldstein, & C. J. Golden (Eds.), Clinical application of neuropsychological
test batteries (pp. 155-192). New York and London: Plenum Press.

Stirling, J. (2002). Introducing neuropsychology. New York, NY: Psychology Press.

St. John, S. (2008). Neuropsychological tests. Retrieved April 24, 2008, from Rollins
College, Blackboard Web site: http://blackboard.rollins.edu/webapps/portal/
frameset.jsp?tab=course&url=bin/common/course.pl?course_id=5963_1

Halstead-Reitan battery

Cmcfall — Sun, 27 Apr 2008 22:13:40 GMT

Cmcfall:

[[Category:Neuropsychological methods]]

==Introduction==

Poor performance on tests of neuropsychological assessment indicates either localized or widespread brain damage in an individual (Stirling, 24). Such tests provide the advantage of comparing a patientâ��s test scores to â��standardizedâ�� scores by other respondents. In addition, these scores show changes in cognition that may relate to progression of an illness or recovery after an injury (Stirling, 24). To test for these impairments or advances, a series of tests is usually administered and often referred to as a test battery. The Halstead-Reitan Battery (HRB) is the most commonly used and evaluates â��measures of verbal and nonverbal intelligence, language, tactile and manipulative skills, auditory sensitivity, and so onâ�� (Stirling, 24).

==History and Development==

Dr. Ward Halstead and Dr. Ralph Reitan were responsible for the development of the HRB. As early as the 1930s, Dr. Halsteadâ��s use of research techniques enabled the accurate identification of localized lesions in the brain (Parsons, 156). During this time, a more holistic approach to neuropsychological assessment was taken, in that brain damage was thought to be more global, rather than attributable to impairments in specific cognitive functions and domains. At the University of Chicago, Ralph Reitan, was one of Halsteadâ��s doctoral students and later went on to publish an article, in which a study of 50 individuals proved to quantitatively separate nearly all of the brain-damaged participants from their age/sex matched controls, thereby confirming the validity of Halsteadâ��s initial findings (Parsons, 156).

At the time of this discovery, inferences about localized lesions came largely from the realms of neurology and neurosurgery, thus questioning the reliability of this battery as well as the ability to generalize the findings to other populations, including patients in psychiatry (Parsons, 157). Later, Dr. Reitan began to move beyond his original cases and extended his results to other participants and again was able to make accurate predictions about â��the lateralization, localization, and the nature of the disorder itselfâ�� (Parsons, 157). The growth and the development of the HRB continues to receive recognition throughout the scientific community and has gradually become the most widespread battery.

==Tests Administered==

Any interpretation of the results from the HRB should consider the variables of age, education, and sex, as well any indication of peripheral injuries. Additionally, hand and eye preference should also be documented, for these inclinations provide important implications in reference to laterality (Parsons, 163). Emotional reactions, attitudes, and any other limitations of the patient should be noted (i.e. a patientâ��s drug administration), which may profoundly impact the interpretation of the results. An accurate interpretation of the test scores relies on a trained psychologist or a professional examiner due to its complex nature. This costly battery takes between five and six hours and requires patience and stamina from both the examiner and patient (Loring & Meador, 1995). The following measures most commonly assessed in neuropsychological evaluations are summarized. (*'''Note''': the tests highlighted in '''bold''' indicate in-class administration and brief instructions are provided).

'''General Intelligence and Achievement'''

The general level of functioning is assessed using the Wechsler Adult Intelligence Scale-Revised (WAIS-R), where full scale, verbal, and performance IQs are reported. Also, the Wide Range Achievement Test (WRAT) scores on subtests of reading, spelling, and arithmetic indicate a participantâ��s current level of performance (Parsons, 169).

'''Sensory-Perceptual and Sensory-Motor Functioning'''

To test for sensory-perceptual ability, Finger agnosia and impairments in finger tip writing recognition recordings provide important data for the visual, auditory, and tactile modalities (Parsons, 169). Sensory-Motor functioning is measured using the Finger Tapping test, the Purdue or Grooved Pegboard tests, or Grip Strength tests, which provide implications for data involving questions of lateralization and localization. Also, the '''Tactual Performance Test (TPT)''' requires an individual to place shapes in a board while being blindfolded. Following completion of this task, the patient is often asked to draw an illustration of the board from memory (St. John, 2008). Left or ride side deficits give insight about lateralization, whereas any suppressive impulses highlight widespread functionary impairments, instead of specific, or localized brain deficits (Parsons, 169).

'''Attention, Concentration, and Memory'''

The importance of these tests lies in their ability to detect brain dysfunction, including laterality. The Wechsler Memory Scale (WMS) or its revised version (WMS-R) is the most common subtest that is used to assess memory. The most prevalent subtests of this Scale include measures of Logical Memory, Visual Reproduction, and Paired Associate Learning (Loring & Meador, 1995). Despite the limitations, which refer to the inability to provide adequate normative data, it is still the most common measure administered.

The Memory Assessment Scales is another collaboration of subtests, although it is less popular and differs in content than those items provided on the WMS. However, it is still sufficient in detecting lateralized dysfunction in candidates for anterior temporal lobectomy. Overall, the Memory Assessment Scales is a series of tests quite similar to those administered for the WMS, but also provides a general memory measure as well as verbal and visual memory subtest scores (Loring & Meador, 1995).

The '''Trial making test''' and the '''Digit Span''' are measures that show sensitivity to attentional impairments. The '''Trial making test''' requires an individual to first make connections between a series of numbers, which is referred to as Trial A. For patients with frontal damage, Trial B is more sensitive, in that the individual is now asked to connect letters with a series of numbers (e.g. A to 1, B to 2, C to 3) and this switching of tasks now demands the use of a different set of â��thinkingâ�� skills (St. John, 2008). This transition has proven to be challenging for such patients. The '''Digit Span''' includes a series of tasks that are auditorily presented to the individual. Starting with a smaller set of randomly arranged numbers, these series are to be verbally repeated back in the original or reverse order to the experimenter. The set of numbers increases with each trial and subsequent lines do not use similar arrangements of numbers as the previous tasks (St. John, 2008).

'''Executive/ â��Frontalâ�� Functions'''

The Category Test, the '''Trial making test''', and the '''Wisconsin Carding Sorting Test (WCST)''' provide accurate measures of executive or frontal lobe functioning. The '''WCST''' presents the patient with a deck of cards that are to be categorized (e.g. shape, color, number, etc), which is predetermined by the experimenter without the participantâ��s knowledge of this choosing. As the cards are shown to the individual, he/she is required to guess which sorting principle the experimenter has chosen. After clear indication of the participantâ��s discovery of the category, the sorting principle is changed without notifying the individual. Scores are based on the number of errors the participant makes in guessing which sorting principle is being used. Poor performance on such a task implies the failure to inhibit a motor program, a deficit termed â��perseveranceâ�� (St. John, 2008).

'''Language and Communication Skills'''

The Reading and Spelling tests from the WRAT, the Aphasia Screening Test, as well as the Vocabulary subtest from the WAIS, provided with a patientâ��s educational background, are all used to measure language skills and possible impairments (Loring & Meador, 1995). Additionally, a patientâ��s nontest related verbal communicative skills (e.g. word finding difficulties) could provide very informative data in predicting relevant dysfunctions (Parsons, 170). For instance, the '''Controlled Oral Word Association''' allows the patient 60 seconds to name as many words as possible beginning with a chosen letter (e.g. â��Câ��). The second and third trials are conducted in the same manner, but two different letters are selected based on the reported difficulty to retrieve words that begin with those letters (e.g. â��Fâ�� and â��Lâ��). An average of 15 words produced is sufficient in normal patients; however, the increasing difficulty of subsequent word associations results in an expected reduction of responses for patients with language and communication deficits (St. John, 2008).

'''Calculational Skills'''

On the Arithmetic subtest of the WAIS-R, the patient is required to retain information via memory when problems are presented to him/her orally. Conversely, the WRAT arithmetic allows the patient to use pencil and paper as a means of calculating problems that are presented visually (Parsons, 171). Difficulties with the use of symbols provide evidence of left-hemisphere lesions, whereas visual-spatial deficits predict right-hemisphere lesions. Finally, the Aphasia Screening Test presents two mathematical problems; one presented auditorily and the other requiring the participant to copy a problem and then solve it (Parsons, 171).

'''Spatial Relationships'''

Subtests of the WAIS-R including the '''Block Design''' test and '''Rey-Osterreith Complex Figure''' test are the most commonly administered assessments of visual spatial aptitude. The '''Block Design''' test presents an individual with a set of blocks that are to be arranged based upon a predetermined pattern. Scores are based on the amount of time it takes the participant to successfully recreate the design (St. John, 2008). The '''Rey-Osterreith Complex Figure''' test varies in instructional administration, with the participant being asked to draw the complex figure from memory, as a copy, or by section. Other times, the novel way in which the figure is reproduced can sometimes be of interest for researchers (St. John, 2008). Additional administrations of spatial ability may include the Bender Gestalt test; however, it has limitations of poor standardization and scoring criteria and is frequently used to evaluate visual motor functioning (Loring & Meador, 1995). Finally, the Visual Retention Test, Judgement of Line Orientation and Facial Recognition Tests (e.g. Benton and Hooper Visual Organization Test) are also commonly used tests to measure spatial aptitude (Loring & Meador, 1995).

'''Learning'''

General information from the WAIS-R is used as a means of providing data on a patientâ��s ability to obtain information from his/her environment and to remember it. High scores on this measure predict pre-morbid attainment, whereas low scores indicate â��lack of attainment, learning disabilities as a child, poor educational opportunities, and brain dysfunction effects on memory and communicationâ�� (Parsons, 172). The WMS also provides paired associates of learning both new/difficult as well as old/easy paired associates, particularly in elderly patients, where dementia is suspected. The WAIS Digit-Symbol test, improvement or lack of on the Luria words, and scores on the Tactual Performance Test (TPT) also reflect issues of learning, particularly the ability to retain new information (Parsons, 172).

'''Abstracting'''

Performance on the WAIS that refers to verbal abstracting ability is able to predict left-hemisphere or generalized brain dysfunction. The Category Test, in which a stimulus set is given to the participant and then required to organize it by obeying a set of rules, is used as a measure of nonverbal abstracting aptitude. This task has proven to be particularly sensitive to all types of brain dysfunctions (Parsons, 172).

'''Problem Solving'''

The '''TPT''' test is commonly used to measure problem-solving skills, which assesses the patientâ��s strategy usage and approaches to solving problems. The Category test, the '''Block Design''' Test, and the '''Trial making test''' are other instruments that test for problem solving as well as set flexibility and perseverance. These tests coupled with the Digit Symbol Test and the '''TPT''' test reveal that most sensitivity to brain damages and aging in patients (Parsons, 173).

'''Personality'''

The Minnesota Multiphasic Personality Inventory (MMPI) provides useful information in diagnosis and treatment. However, this test, along with others, is inadequate in determining whether depressive scores are the cause or the reaction to brain injury (Parsons, 173). While personality tests are not always employed, they are often administered more times than not, particularly to evaluate if personality characteristics are significant factors, and more specifically in patients who report back pain prior to or following back surgery (Loring & Meador, 1995). Overall, personality tests are used as a means of assessing which treatment approach will produce the most effective results (Parsons, 173).

==Limitations==

The original norms for the Halstead tests are based on a relatively small and young sample, resulting in diagnostic issues and potential faulty conclusions (Lezak, 710). However, age-graded norms are now available for means of comparison that include gender and education variables. Also, these tests have been questioned in the elderly population, as they have been shown to be too lengthy and challenging for these individuals (Lezak, 710). Thus, Halsteadâ��s core scores have not been included in batteries that evaluate such patients. Nevertheless, the HRBâ��s accuracy and validity still relies on its ability to predict the nature, the presence, as well as the site of a lesion by employing statistical relationships between test scores (Lezak, 710).

==Neuropsychological Findings==

Interpretations of the HRB have proven to be highly accurate in correct predictions. However, the battery has been questioned for its lengthy administration and lack of diagnostic efficiency (Loring & Meador, 1995). While, the mere length of the HRB has shown to be less appropriate for patients in whom attentional issues are present, its most significant contribution comes from its ability to address a variety of behaviors in relation to neuropsychological functioning (Lezak, 712). Variations of the HRB have been used in studies in an effort to indicate more specific brain dysfunctions, for they provide greater sensitivity to test performance of patients (Lezak, 713). More plainly stated, specific tests are selected to test for particular hypotheses about an individual (Stirling, 25). Overall, batteries provide information about changes in cognitive functioning that are helpful for diagnostic purposes, but more importantly, in the efficacy of treatment and recovery.

==References==

Lezak, M. D. (1995). Batteries for assessment of brain damage. In, Neuropsychological assessment (3rd ed., pp. 686-735). New York: Oxford University Press.

Loring, D. W., & Meador, K. J. (1995, May 12). Neuropsychology for neurologists.
Paper presented at the Annual Meeting of the American Academy of Neurology,
Seattle, Washington. Retrieved April 24, 2008, from http://www.nldontheweb.org
/loring-meador.htm

Parsons, O. A. (1986). Overview of the halsted-reitan battery. In T. Incagnoli, G.
Goldstein, & C. J. Golden (Eds.), Clinical application of neuropsychological
test batteries (pp. 155-192). New York and London: Plenum Press.

Stirling, J. (2002). Introducing neuropsychology. New York, NY: Psychology Press.

St. John, S. (2008). Neuropsychological tests. Retrieved April 24, 2008, from Rollins
College, Blackboard Web site: http://blackboard.rollins.edu/webapps/portal/
frameset.jsp?tab=course&url=bin/common/course.pl?course_id=5963_1

Lawrence Weiskrantz

Cmcfall — Sun, 27 Apr 2008 22:03:21 GMT

Cmcfall:

[[Category:Neuropsychological profiles]]

==Biographical Overview==

[[Image:weiskrantz.jpg]]

Lawrence Weiskrantz is a well-known neuropsychologist, whose most notable contribution stems from his work with individuals suffering from amnesia and blindsight (a condition he discovered) over the past few decades. The 'blindsight' phenomenon has remarkably helped to clarify or explain the role of the primary visual projection region of the cortex in visual ability after damage to this area has occurred. His landmark research, in which contemporary models of different memory systems were revealed, has been widely recognized by modern researchers and scientists.

He obtained his B.Sc. degree from Oxford University and then his PhD from Harvard University in 1953. Dr. Weiskrantz held a teaching position at Cambridge University in the late 1950s and after years of extensive lectures and research, he later worked at the Oxford University and was also appointed Director of the Department of Experimental Psychology from 1967 to 1993.
He is currently Emeritus (retired, but still honorably retains his title) Professor in the psychology department at Oxford University. Additionally, Dr. Weiskrantz is Fellow of the Royal Society of London for the Improvement of Natural Knowledge, more commonly referred to as the Royal Society, as well as a member of the U.S. National Academy of Sciences. In 1989, he delivered the Royal Society's Ferrier Lecture. Dr. Weiskrantz is also a distinguished author and his wide-ranging knowledge and research experience has earned him numerous awards of unprecedented recognition. These awards and publications are summarized.

'''Awards'''

-Craik Prize from Cambridge

-Hughlings Jackson Medal from the Royal Society of Medicine

-William James Fellowship of the American Psychological Society, 1992

'''Publications'''

-Analysis of Behavioral Change, 1967

-Inroad and Detours in Psychology, 1970

-Associated Humane Societies Directory, 1980

-The Neuropsychology of Cognitive Function, 1982

-Animal Intelligence, 1985

-Blindsight: A Case Study and Implications, 1986

Thought Without Language, 1988

-Consciousness Lost and Found: A Neuropsychological Foundation, 1997

-Percepts, brain imaging, and the certainty principle: A triangular approach to the scientific basis of consciousness (Herbert H. Reynoldâ��s lectureship in the history and philosophy of science), 1999

'''Co-Author Publications'''

-The Neuropsychology of Cognitive Function: proceedings of a Royal Society, 1982

-Attention: Selection, Awareness, and Control: A Tribute to Donald Broadbent, 1993

-The Prefrontal Cortex: Executive and Cognitive Functions, 1998

-Frontiers of Consciousness, 2008

==References==

Association for Psychological Science, William James Fellow Award 1992. (n.d.).
Retrieved April 23, 2008, from http://www.psychologicalscience.org/awards/
james/citations/weiskrantz.cfm

Baylor University, The Herbert Reynolds Lecture Series (1999). Lawrence weiskrantz.
Retrieved April 20, 2008, from http://www.baylor.edu/reynold_lecture_series/
index.php?id=38921

Stanford University, The Stanford Humanities Center (1997, October). The harry camp
memorial lectures. Retrieved April 20, 2008, from http://shc.stanford.edu/shc/
1997-1998/events/weiskrantz.html

File:Weiskrantz.jpg

Cmcfall — Sun, 27 Apr 2008 22:02:45 GMT

Cmcfall:

Lawrence Weiskrantz

Cmcfall — Sun, 27 Apr 2008 22:02:31 GMT

Cmcfall:

[[Category:Neuropsychological profiles]]

==Biographical Overview==

Lawrence Weiskrantz is a well-known neuropsychologist, whose most notable contribution stems from his work with individuals suffering from amnesia and blindsight (a condition he discovered) over the past few decades. The 'blindsight' phenomenon has remarkably helped to clarify or explain the role of the primary visual projection region of the cortex in visual ability after damage to this area has occurred. His landmark research, in which contemporary models of different memory systems were revealed, has been widely recognized by modern researchers and scientists.

He obtained his B.Sc. degree from Oxford University and then his PhD from Harvard University in 1953. Dr. Weiskrantz held a teaching position at Cambridge University in the late 1950s and after years of extensive lectures and research, he later worked at the Oxford University and was also appointed Director of the Department of Experimental Psychology from 1967 to 1993.
He is currently Emeritus (retired, but still honorably retains his title) Professor in the psychology department at Oxford University. Additionally, Dr. Weiskrantz is Fellow of the Royal Society of London for the Improvement of Natural Knowledge, more commonly referred to as the Royal Society, as well as a member of the U.S. National Academy of Sciences. In 1989, he delivered the Royal Society's Ferrier Lecture. Dr. Weiskrantz is also a distinguished author and his wide-ranging knowledge and research experience has earned him numerous awards of unprecedented recognition. These awards and publications are summarized.

'''Awards'''

-Craik Prize from Cambridge

-Hughlings Jackson Medal from the Royal Society of Medicine

-William James Fellowship of the American Psychological Society, 1992

'''Publications'''

-Analysis of Behavioral Change, 1967

-Inroad and Detours in Psychology, 1970

-Associated Humane Societies Directory, 1980

-The Neuropsychology of Cognitive Function, 1982

-Animal Intelligence, 1985

-Blindsight: A Case Study and Implications, 1986

Thought Without Language, 1988

-Consciousness Lost and Found: A Neuropsychological Foundation, 1997

-Percepts, brain imaging, and the certainty principle: A triangular approach to the scientific basis of consciousness (Herbert H. Reynoldâ��s lectureship in the history and philosophy of science), 1999

'''Co-Author Publications'''

-The Neuropsychology of Cognitive Function: proceedings of a Royal Society, 1982

-Attention: Selection, Awareness, and Control: A Tribute to Donald Broadbent, 1993

-The Prefrontal Cortex: Executive and Cognitive Functions, 1998

-Frontiers of Consciousness, 2008

==References==

Association for Psychological Science, William James Fellow Award 1992. (n.d.).
Retrieved April 23, 2008, from http://www.psychologicalscience.org/awards/
james/citations/weiskrantz.cfm

Baylor University, The Herbert Reynolds Lecture Series (1999). Lawrence weiskrantz.
Retrieved April 20, 2008, from http://www.baylor.edu/reynold_lecture_series/
index.php?id=38921

Stanford University, The Stanford Humanities Center (1997, October). The harry camp
memorial lectures. Retrieved April 20, 2008, from http://shc.stanford.edu/shc/
1997-1998/events/weiskrantz.html

Lawrence Weiskrantz

Cmcfall — Sun, 27 Apr 2008 22:00:17 GMT

Cmcfall:

[[Category:Neuropsychological profiles]]

==Biographical Overview==

[[Image:weiskrantz.jpeg]]

Lawrence Weiskrantz is a well-known neuropsychologist, whose most notable contribution stems from his work with individuals suffering from amnesia and blindsight (a condition he discovered) over the past few decades. The 'blindsight' phenomenon has remarkably helped to clarify or explain the role of the primary visual projection region of the cortex in visual ability after damage to this area has occurred. His landmark research, in which contemporary models of different memory systems were revealed, has been widely recognized by modern researchers and scientists.

He obtained his B.Sc. degree from Oxford University and then his PhD from Harvard University in 1953. Dr. Weiskrantz held a teaching position at Cambridge University in the late 1950s and after years of extensive lectures and research, he later worked at the Oxford University and was also appointed Director of the Department of Experimental Psychology from 1967 to 1993.
He is currently Emeritus (retired, but still honorably retains his title) Professor in the psychology department at Oxford University. Additionally, Dr. Weiskrantz is Fellow of the Royal Society of London for the Improvement of Natural Knowledge, more commonly referred to as the Royal Society, as well as a member of the U.S. National Academy of Sciences. In 1989, he delivered the Royal Society's Ferrier Lecture. Dr. Weiskrantz is also a distinguished author and his wide-ranging knowledge and research experience has earned him numerous awards of unprecedented recognition. These awards and publications are summarized.

'''Awards'''

-Craik Prize from Cambridge

-Hughlings Jackson Medal from the Royal Society of Medicine

-William James Fellowship of the American Psychological Society, 1992

'''Publications'''

-Analysis of Behavioral Change, 1967

-Inroad and Detours in Psychology, 1970

-Associated Humane Societies Directory, 1980

-The Neuropsychology of Cognitive Function, 1982

-Animal Intelligence, 1985

-Blindsight: A Case Study and Implications, 1986

Thought Without Language, 1988

-Consciousness Lost and Found: A Neuropsychological Foundation, 1997

-Percepts, brain imaging, and the certainty principle: A triangular approach to the scientific basis of consciousness (Herbert H. Reynoldâ��s lectureship in the history and philosophy of science), 1999

'''Co-Author Publications'''

-The Neuropsychology of Cognitive Function: proceedings of a Royal Society, 1982

-Attention: Selection, Awareness, and Control: A Tribute to Donald Broadbent, 1993

-The Prefrontal Cortex: Executive and Cognitive Functions, 1998

-Frontiers of Consciousness, 2008

==References==

Association for Psychological Science, William James Fellow Award 1992. (n.d.).
Retrieved April 23, 2008, from http://www.psychologicalscience.org/awards/
james/citations/weiskrantz.cfm

Baylor University, The Herbert Reynolds Lecture Series (1999). Lawrence weiskrantz.
Retrieved April 20, 2008, from http://www.baylor.edu/reynold_lecture_series/
index.php?id=38921

Stanford University, The Stanford Humanities Center (1997, October). The harry camp
memorial lectures. Retrieved April 20, 2008, from http://shc.stanford.edu/shc/
1997-1998/events/weiskrantz.html

File:Weiskrantz.jpeg

Cmcfall — Sun, 27 Apr 2008 21:58:38 GMT

Cmcfall:

Lawrence Weiskrantz

Cmcfall — Sun, 27 Apr 2008 21:57:57 GMT

Cmcfall:

Lawrence Weiskrantz

Cmcfall — Sun, 27 Apr 2008 21:57:03 GMT

Cmcfall:

[[Category:Neuropsychological profiles]]

==Biographical Overview==

Lawrence Weiskrantz is a well-known neuropsychologist, whose most notable contribution stems from his work with individuals suffering from amnesia and blindsight (a condition he discovered) over the past few decades. The 'blindsight' phenomenon has remarkably helped to clarify or explain the role of the primary visual projection region of the cortex in visual ability after damage to this area has occurred. His landmark research, in which contemporary models of different memory systems were revealed, has been widely recognized by modern researchers and scientists.

He obtained his B.Sc. degree from Oxford University and then his PhD from Harvard University in 1953. Dr. Weiskrantz held a teaching position at Cambridge University in the late 1950s and after years of extensive lectures and research, he later worked at the Oxford University and was also appointed Director of the Department of Experimental Psychology from 1967 to 1993.
He is currently Emeritus (retired, but still honorably retains his title) Professor in the psychology department at Oxford University. Additionally, Dr. Weiskrantz is Fellow of the Royal Society of London for the Improvement of Natural Knowledge, more commonly referred to as the Royal Society, as well as a member of the U.S. National Academy of Sciences. In 1989, he delivered the Royal Society's Ferrier Lecture. Dr. Weiskrantz is also a distinguished author and his wide-ranging knowledge and research experience has earned him numerous awards of unprecedented recognition. These awards and publications are summarized.

'''Awards'''

-Craik Prize from Cambridge
-Hughlings Jackson Medal from the Royal Society of Medicine
-William James Fellowship of the American Psychological Society, 1992

'''Publications'''

-Analysis of Behavioral Change, 1967
-Inroad and Detours in Psychology, 1970
-Associated Humane Societies Directory, 1980
-The Neuropsychology of Cognitive Function, 1982
-Animal Intelligence, 1985
-Blindsight: A Case Study and Implications, 1986
Thought Without Language, 1988
-Consciousness Lost and Found: A Neuropsychological Foundation, 1997
-Percepts, brain imaging, and the certainty principle: A triangular approach to the scientific basis of consciousness (Herbert H. Reynoldâ��s lectureship in the history and philosophy of science), 1999

'''Co-Author Publications'''

-The Neuropsychology of Cognitive Function: proceedings of a Royal Society, 1982
-Attention: Selection, Awareness, and Control: A Tribute to Donald Broadbent, 1993
-The Prefrontal Cortex: Executive and Cognitive Functions, 1998
-Frontiers of Consciousness, 2008

==References==

Association for Psychological Science, William James Fellow Award 1992. (n.d.).
Retrieved April 23, 2008, from http://www.psychologicalscience.org/awards/
james/citations/weiskrantz.cfm

Baylor University, The Herbert Reynolds Lecture Series (1999). Lawrence weiskrantz.
Retrieved April 20, 2008, from http://www.baylor.edu/reynold_lecture_series/
index.php?id=38921

Stanford University, The Stanford Humanities Center (1997, October). The harry camp
memorial lectures. Retrieved April 20, 2008, from http://shc.stanford.edu/shc/
1997-1998/events/weiskrantz.html

Lawrence Weiskrantz

Cmcfall — Sun, 27 Apr 2008 21:54:42 GMT

Cmcfall:

[[Category:Neuropsychological profiles]]

==Biographical Overview==

Lawrence Weiskrantz is a well-known neuropsychologist, whose most notable contribution stems from his work with individuals suffering from amnesia and blindsight (a condition he discovered) over the past few decades. The 'blindsight' phenomenon has remarkably helped to clarify or explain the role of the primary visual projection region of the cortex in visual ability after damage to this area has occurred. His landmark research, in which contemporary models of different memory systems were revealed, has been widely recognized by modern researchers and scientists.

He obtained his B.Sc. degree from Oxford University and then his PhD from Harvard University in 1953. Dr. Weiskrantz held a teaching position at Cambridge University in the late 1950s and after years of extensive lectures and research, he later worked at the Oxford University and was also appointed Director of the Department of Experimental Psychology from 1967 to 1993.
He is currently Emeritus (retired, but still honorably retains his title) Professor in the psychology department at Oxford University. Additionally, Dr. Weiskrantz is Fellow of the Royal Society of London for the Improvement of Natural Knowledge, more commonly referred to as the Royal Society, as well as a member of the U.S. National Academy of Sciences. In 1989, he delivered the Royal Societyâ��s Ferrier Lecture. Dr. Weiskrantz is also a distinguished author and his wide-ranging knowledge and research experience has earned him numerous awards of unprecedented recognition. These awards and publications are summarized.

'''Awards'''

Craik Prize from Cambridge

Hughlings Jackson Medal from the Royal Society of Medicine

William James Fellowship of the American Psychological Society, 1992

'''Publications'''

Analysis of Behavioral Change, 1967

Inroad and Detours in Psychology, 1970

Associated Humane Societies Directory, 1980

The Neuropsychology of Cognitive Function, 1982

Animal Intelligence, 1985

Blindsight: A Case Study and Implications, 1986
Thought Without Language, 1988

Consciousness Lost and Found: A Neuropsychological Foundation, 1997

Percepts, brain imaging, and the certainty principle: A triangular approach to the scientific basis of consciousness (Herbert H. Reynoldâ��s lectureship in the history and philosophy of science), 1999

'''Co-Author Publications'''

The Neuropsychology of Cognitive Function: proceedings of a Royal Society, 1982

Attention: Selection, Awareness, and Control: A Tribute to Donald Broadbent, 1993

The Prefrontal Cortex: Executive and Cognitive Functions, 1998

Frontiers of Consciousness, 2008

==References==

Association for Psychological Science, William James Fellow Award 1992. (n.d.).
Retrieved April 23, 2008, from http://www.psychologicalscience.org/awards/
james/citations/weiskrantz.cfm

Baylor University, The Herbert Reynolds Lecture Series (1999). Lawrence weiskrantz.
Retrieved April 20, 2008, from http://www.baylor.edu/reynold_lecture_series/
index.php?id=38921

Stanford University, The Stanford Humanities Center (1997, October). The harry camp
memorial lectures. Retrieved April 20, 2008, from http://shc.stanford.edu/shc/
1997-1998/events/weiskrantz.html

Lawrence Weiskrantz

Cmcfall — Sun, 27 Apr 2008 21:52:35 GMT

Cmcfall:

[[Category:Neuropsychological profiles]]

==Biographical Overview==

Lawrence Weiskrantz is a well-known neuropsychologist, whose most notable contribution stems from his work with individuals suffering from amnesia and blindsight (a condition he discovered) over the past few decades. The â��blindsightâ�� phenomenon has remarkably helped to clarify or explain the role of the primary visual projection region of the cortex in visual ability after damage to this area has occurred. His landmark research, in which contemporary models of different memory systems were revealed, has been widely recognized by modern researchers and scientists.

He obtained his B.Sc. degree from Oxford University and then his PhD from Harvard University in 1953. Dr. Weiskrantz held a teaching position at Cambridge University in the late 1950s and after years of extensive lectures and research, he later worked at the Oxford University and was also appointed Director of the Department of Experimental Psychology from 1967 to 1993.
He is currently Emeritus (retired, but still honorably retains his title) Professor in the psychology department at Oxford University. Additionally, Dr. Weiskrantz is Fellow of the Royal Society of London for the Improvement of Natural Knowledge, more commonly referred to as the Royal Society, as well as a member of the U.S. National Academy of Sciences. In 1989, he delivered the Royal Societyâ��s Ferrier Lecture. Dr. Weiskrantz is also a distinguished author and his wide-ranging knowledge and research experience has earned him numerous awards of unprecedented recognition. These awards and publications are summarized.

'''Awards'''

â�¢Craik Prize from Cambridge
â�¢Hughlings Jackson Medal from the Royal Society of Medicine
â�¢William James Fellowship of the American Psychological Society, 1992

'''Publications'''

â�¢Analysis of Behavioral Change, 1967
â�¢Inroad and Detours in Psychology, 1970
â�¢Associated Humane Societies Directory, 1980
â�¢The Neuropsychology of Cognitive Function, 1982
â�¢Animal Intelligence, 1985
â�¢Blindsight: A Case Study and Implications, 1986
â�¢Thought Without Language, 1988
â�¢Consciousness Lost and Found: A Neuropsychological Foundation, 1997
â�¢Percepts, brain imaging, and the certainty principle: A triangular approach to the scientific basis of consciousness (Herbert H. Reynoldâ��s lectureship in the history and philosophy of science), 1999

'''Co-Author Publications'''

â�¢The Neuropsychology of Cognitive Function: proceedings of a Royal Society, 1982
â�¢Attention: Selection, Awareness, and Control: A Tribute to Donald Broadbent, 1993
â�¢The Prefrontal Cortex: Executive and Cognitive Functions, 1998
â�¢Frontiers of Consciousness, 2008

==References==

Association for Psychological Science, William James Fellow Award 1992. (n.d.).
Retrieved April 23, 2008, from http://www.psychologicalscience.org/awards/
james/citations/weiskrantz.cfm

Baylor University, The Herbert Reynolds Lecture Series (1999). Lawrence weiskrantz.
Retrieved April 20, 2008, from http://www.baylor.edu/reynold_lecture_series/
index.php?id=38921

Stanford University, The Stanford Humanities Center (1997, October). The harry camp
memorial lectures. Retrieved April 20, 2008, from http://shc.stanford.edu/shc/
1997-1998/events/weiskrantz.html

Phantom limbs

Cmcfall — Sun, 27 Apr 2008 21:49:09 GMT

Cmcfall:

[[Category:Neuropsychological syndromes]]

==Overview==

Phantom limbs is a disorder of peripersonal space, in which deficits in the spatial boundary of the visual receptive fields are observed. Most notably, it refers to a sense of outstanding and often painful feeling (98% of reported cases) from an amputated body part, such as the arms or legs, which is usually most pronounced following surgery and becomes lessened overtime (Silvano, Berger, Keith, & Brodie, 1974-1986). These sensations are not limited to pain, but also include touch, temperature, wetness, and movement that arise from the no longer existent body part (Stirling, 65). It should also be noted that this phenomenon is not metaphorical in nature, but rather a sensation that is actually felt by such individuals. In fact, the realistic nature of phantom limbs is such that a patient may actually forget that a body part has been removed and attempts to use the missing limb have been widely reported (Stirling, 66). The patient also tends to exhibit a greater conscious awareness of the phantom than the opposite, intact limb (Silvano & Reiser, 1974-1986). The three most common types of the phantom are: a mild, tingling feeling; a momentary “pins and needles” sensation; and painful feelings such as “twisting,” “burning,” “itching,” and “pulling” (Silvano & Reiser, 1974-1986).

As mentioned, most individuals experience pain that can be modified or reduced via surgical procedures, but these operations have often failed to fully eliminate such displeasure (Silvano & Reiser, 1974-1986). The ineffectiveness to diminish painful phantom limb experiences was further explored as anecdotal evidence was collected to provide insight about the underlying mechanisms of this phenomenon. Moreover, case reports have shown that stimulation of body regions aligned with the cortical receptive fields adjacent to the amputated limb can elicit the phantom experience (Stirling, 66). Ramachandaran explained the effects of such experiences by proposing that sensory inputs travel to both target and neighboring regions and that normally, the adjacent regions are inhibited by direct inputs to the region. However, when these inputs are absent, commonly referred to as lateral disinhibition, the nearby regions now receive the cortical inputs, thereby evoking the phantom limb phenomenon (Stirling, 67). While Ramachandran’s assertion alone cannot account for all aspects of the experience, these findings not only highlight the need to establish methods of recovery, but they also serve as reminder that the developmental aspect of plasticity can still occur, even in mature adults (Stirling, 68).

[[Image:phantomlimbpain.gif]]

==Neural Plasticity==

Ramachandran (1993) reported plastic changes that were observed in the visual cortex of the brain and referred to this occurrence as the “filling in” phenomenon, in which the loss of visual abilities (e.g. scotomas) caused rapid changes in the reorganization of the primary visual receptive fields. These findings led the researcher to question similar effects of other adult somatosensory pathways, including touch and hearing. Earlier studies found that after long durations of amputation, the cortical area initially corresponding to the hand was now replaced by sensory input from the ipsilateral face region. Thus, the results of these studies coupled with Ramachandran’s previous experiment generated the remapping hypothesis, which asserts the ability of the receptive fields to be temporarily expanded to proximal areas due to the “unmasking” of pre-existing neural connections, rather than the development or sprouting of new ones (Ramachandran, 1993).

Results of the study on individuals with phantom limbs, revealed a one-to-one correspondence between points on the patient’s fingers as well as on the face, which were not randomly represented, but observed on the lower face region and the area near deafferentation (Ramachandran, 1993). Additionally, it was further suggested that complex sensations distal from the region of amputation could be referred, which occur at a rapid rate of reorganization. Thus, modality-specific “rewiring” can effectively occur even after short periods of stimulus deprivation, thereby supporting Ramachandran’s hypothesis that phantom limb experience arises from spontaneous activity of tissues in the face and those near the amputated limb (Ramachandran, 1993). It was also thought that reafferance signals are combined with motor commands that are then sent to the muscle(s) of the phantom limb and to some degree, from neuromas, or tumors that are comprised of nerve tissues (Ramachandran, 1993). The information from these sources is lastly processed in the parietal cortex, which gives rise to the experience, where an image of the nonexistent body part persists. However, in response to the researcher’s own assertions, extensive studies investigating the biological, pre-existing neural connections have failed to find significant results that would support the “unmasking” hypothesis Ramachandran proposed, thereby giving greater rise to the sprouting hypothesis. If such sprouting were the case, these growths would require precise and rapid cortical reorganization to enable topography to take place as well as the occurrence of complex sensations such as “gripping,” or “trickling” (Ramachandran, 1993). While this study proved to be somewhat inconclusive in that the neither of the competing hypotheses was firmly established, the rapid changes in the topographical maps implied the need for future revision of the stable or unchanging views of cortical receptive fields.

Later, Ramachandran and Rogers-Ramachandran (2000) further explored the remapping hypothesis and indeed found that unmasking of pre-existing neural connections can be referred even hours after amputation. Similar to the results in the abovementioned study, an earlier experiment on adult monkeys revealed the topographic reorganization when a stimulus was presented to a side of the face that corresponded to the hand in the cortical somatotopic map. Following this finding, magnetoencephalographic experiments showed similar results in the adult human cortex, in that the referred feelings were modality-specific (Ramachandran & Rogers-Ramachandran, 2000). For instance, sensations that were delivered to the lower face region were also felt on the phantom limb. In addition, when other parts of the body were similarly stimulated, these sensations were not as pronounced on the phantom; however, evidence showed that a second topographical map was constructed close to the missing body part. Therefore, these results provide evidence for the remapping hypothesis, where sensations occur as a result of the unmasking of pre-existing neural connections, as shown in the rapid topographical reorganization; a finding that was previously challenged (Ramachandran & Rogers- Ramachandran, 2000).

This study also highlighted the role of the conscious experience in brain activity, in that patients initially felt sensations in both the hand and the face, apparently due to the separate activation of these two regions. However, overtime the patient would begin to experience a feeling on the just the face when the hand was touched. This gives rise to a possible “cortical overshooting” during mapping reorganization, so that sensation from the hand is suppressed or masked (Ramachandran & Rogers-Ramachandaran, 2000). Finally, the researchers reported Mirror box experiments, where a patient would place the intact body part in a location that corresponded to the represented limb. Thus, the visual illusion that the phantom limb had been resurrected provided visual feedback that enabled the troubled patient to relieve any reported displeasure that had been previously experienced (Ramachandran & Rogers-Ramachandran, 2000). The importance of these studies showed the interaction between visual and somatosensory modalities, which deal with back-and-forth exchanges, rather than the initially proposed hierarchical neural model. Furthermore, these mirror image studies implied that body image is a malleable, internal construct that is also subject to change, despite its seemingly rigid and fixed appearance (Ramachandran & Rogers-Ramachandran, 2000).

==Body Image==

Body image refers to the internal and actual or idealized image that manifests itself in ways that shape an individual’s personality, self-esteem, and overall psychosocial well-being. In phantom limbs patients, the cerebral representation can be reorganized, so that the phantom is modified and sometimes even dissipated. Often times though, amputation can lead to a distorted body image that is accounted for in emotional, perceptual, and psychosocial reactions (Silvano & Reiser, 1974-1986). This sudden change not only leads to a misrepresentation of the self, but also arouses varying levels of anxiety in such patients. Additionally, denial is a common defense mechanism that cannot only result in failure to report a phantom limb, but also an inability to reorganize an individual’s body image, such that recovery and rehabilitative measures cannot be effectively taken. Consequently, this maladaptation can subsequently lead to embodiment of psychopathological characteristics, which include, but not are not limited to, depression and magical thinking (Silvano & Reiser, 1974-1986). Therefore, attempts to modify the phantom limb can only be successful depending on the relational meaning of the body part to the patient. In other words, if an amputee is unwilling to accept the present body structure, as is, this perceived defect is fully capable of interfering with motivation and recovery as a result of this disturbance (Silvano & Reiser, 1974-1986). Therefore, the unstable nature of a patient’s body image should be fully accounted for in evaluation and treatment of such patients.

[[Image:Phantomlimbs1.jpg]]

==Treatment==

Successful treatment of the disturbed body image arising from the phantom limb phenomenon is dependent upon the current body of knowledge, which unfortunately, has been inadequately implemented in the present social system (Silvano & Reiser, 1974-1986). The ways in which social life is constructed can therefore profoundly affect the self-esteem, or the manner in which a patient perceives him/herself. In cases where the social structure has failed to provide supportive measures, it is vitally crucial for rehabilitative services to appropriately develop procedures that allow for ego enhancement (Silvano & Reiser, 1974-1986). The patient should be made aware of the most commonly reported phantom experiences, and fears and desires about the amputated body part should be addressed. Family, friends, and other environmental influences should also be expected to appropriately respond to such patients, for several studies have shown the detrimental effects that phantom experiences can have on body image and consequently, personality and overall psychological structure and functioning (Silvano & Reiser, 1974-1986). Therefore, these individuals should act as support systems, upon which the patient can reliably depend.

In patients who experience chronic pain, the goal of outside resources is to adopt methods of behavioral reinforcement, or operant mechanisms, which can either, prolong or reduce the individual’s expression of pain. These strategies are referred to as Fordyce’s basic principles of behavior modification (Silvano et al., 1974-1986). The approach here is to alter the patient’s behavior such that he/she can focus on engagement in other areas that enable him/her to withdraw from the reported chronic pain and exert more effortful control over these undesirable experiences. While the aforementioned suggestions regarding this phenomenon have been widely reported, the primary emphasis should remain on the reactions of amputated patients to ensure maximum recovery and restoration of a healthy body image (Silvano et al., 1974-1986).

In similar cases of chronic pain, other forms of therapy can be taken. For instance, Sympathetic Blockade refers to the intravenous infusion of guanethidine by closing off circulation. Shortly after, the patient tends to feel less pain that can sometimes result in complete recovery, but should be repeated to guarantee permanent relief (Silvano et al., 1974-1986). Other approaches to these seemingly endless periods of pain include surgical sympathectomy and chemical sympathectomy, in which destruction of the nerves in the sympathetic system can increase blood flow and reduce pain (Silvano et al., 1974-1986). Similarly, electrical stimulation, intense vibration of the stump, and injections of hypertonic saline have also shown to relieve pain, with duration of success remaining largely dependent upon the patient (Silvano et al., 1974-1986).

Finally, the abovementioned study conducted by Ramachandran and Rogers-Ramachandran (2000) confirmed the temporary, and in some cases permanent, elimination of pain in phantom limbs patients in Mirror box experiments. As previously noted, the ability to project an individual’s intact limb to a corresponding location on the mirror creates the visual illusion of the reported phantom. This visual feedback, in turn, provides these patients with the ability to relieve unwanted sensations (e.g. clenching) pertaining to the non-existent body part (Ramachandran & Rogers-Ramachandran, 2000). However, Mirror box experiments are susceptible to “placebo effects” in relation to reduction of pain, and so it is evident that studies of double-blind control subjects should be conducted. Nonetheless, whether or not this procedure produces favorable outcomes, it should still be noted that the use of visual feedback enables patients to not only see, but also feel corresponding movements in the reported phantom, which therefore gives rise to the conscious experience of this phenomenon (Ramachandran & Rogers-Ramachandran, 2000). Disturbances in an individual’s body-image and/or experience of chronic pain have been largely observed in such patients; however, the extent to which these reactions are reported provide profound implications for which therapy methods will produce the most effective results (Silvano & Reiser, 1974-1986).

==References==

Ramachandran, V. S. (1993). Behavioral and magnetoencephalographic correlates of
plasticity in the adult human brain. Proc. Natl. Acad. Sci. USA, 90, 10413-10420.

Ramachandran, V. S., & Rogers-Ramachandran, D. (2000). Phantom limbs and neural
plasticity. Archives of Neurology, 57, 317-320.

Silvano, A., & Reiser, M. F. (Eds.). (1974-1986). American handbook of psychiatry: Organic disorders and psychosomatic medicine (2nd ed., Vols. 1-8). New York, NY: Basic Books, Inc., Publishers.

Silvano, A., Berger, P. A., Keith, H., & Brodie, H. (Eds.). (1974-1986). American
handbook of psychiatry: Biological psychiatry (2nd ed., Vols. 1-8). New York, NY: Basic Books, Inc., Publishers.

Stirling, J. (2002). Introducing Neuropsychology. New York, NY: Psychology Press.

Phantom limbs

Cmcfall — Sun, 27 Apr 2008 21:48:01 GMT

Cmcfall:

[[Category:Neuropsychological syndromes]]

==Overview==

Phantom limbs is a disorder of peripersonal space, in which deficits in the spatial boundary of the visual receptive fields are observed. Most notably, it refers to a sense of outstanding and often painful feeling (98% of reported cases) from an amputated body part, such as the arms or legs, which is usually most pronounced following surgery and becomes lessened overtime (Silvano, Berger, Keith, & Brodie, 1974-1986). These sensations are not limited to pain, but also include touch, temperature, wetness, and movement that arise from the no longer existent body part (Stirling, 65). It should also be noted that this phenomenon is not metaphorical in nature, but rather a sensation that is actually felt by such individuals. In fact, the realistic nature of phantom limbs is such that a patient may actually forget that a body part has been removed and attempts to use the missing limb have been widely reported (Stirling, 66). The patient also tends to exhibit a greater conscious awareness of the phantom than the opposite, intact limb (Silvano & Reiser, 1974-1986). The three most common types of the phantom are: a mild, tingling feeling; a momentary “pins and needles” sensation; and painful feelings such as “twisting,” “burning,” “itching,” and “pulling” (Silvano & Reiser, 1974-1986).

As mentioned, most individuals experience pain that can be modified or reduced via surgical procedures, but these operations have often failed to fully eliminate such displeasure (Silvano & Reiser, 1974-1986). The ineffectiveness to diminish painful phantom limb experiences was further explored as anecdotal evidence was collected to provide insight about the underlying mechanisms of this phenomenon. Moreover, case reports have shown that stimulation of body regions aligned with the cortical receptive fields adjacent to the amputated limb can elicit the phantom experience (Stirling, 66). Ramachandaran explained the effects of such experiences by proposing that sensory inputs travel to both target and neighboring regions and that normally, the adjacent regions are inhibited by direct inputs to the region. However, when these inputs are absent, commonly referred to as lateral disinhibition, the nearby regions now receive the cortical inputs, thereby evoking the phantom limb phenomenon (Stirling, 67). While Ramachandran’s assertion alone cannot account for all aspects of the experience, these findings not only highlight the need to establish methods of recovery, but they also serve as reminder that the developmental aspect of plasticity can still occur, even in mature adults (Stirling, 68).

[[Image:phantomlimbpain.gif]]

==Neural Plasticity==

Ramachandran (1993) reported plastic changes that were observed in the visual cortex of the brain and referred to this occurrence as the “filling in” phenomenon, in which the loss of visual abilities (e.g. scotomas) caused rapid changes in the reorganization of the primary visual receptive fields. These findings led the researcher to question similar effects of other adult somatosensory pathways, including touch and hearing. Earlier studies found that after long durations of amputation, the cortical area initially corresponding to the hand was now replaced by sensory input from the ipsilateral face region. Thus, the results of these studies coupled with Ramachandran’s previous experiment generated the remapping hypothesis, which asserts the ability of the receptive fields to be temporarily expanded to proximal areas due to the “unmasking” of pre-existing neural connections, rather than the development or sprouting of new ones (Ramachandran, 1993).

Results of the study on individuals with phantom limbs, revealed a one-to-one correspondence between points on the patient’s fingers as well as on the face, which were not randomly represented, but observed on the lower face region and the area near deafferentation (Ramachandran, 1993). Additionally, it was further suggested that complex sensations distal from the region of amputation could be referred, which occur at a rapid rate of reorganization. Thus, modality-specific “rewiring” can effectively occur even after short periods of stimulus deprivation, thereby supporting Ramachandran’s hypothesis that phantom limb experience arises from spontaneous activity of tissues in the face and those near the amputated limb (Ramachandran, 1993). It was also thought that reafferance signals are combined with motor commands that are then sent to the muscle(s) of the phantom limb and to some degree, from neuromas, or tumors that are comprised of nerve tissues (Ramachandran, 1993). The information from these sources is lastly processed in the parietal cortex, which gives rise to the experience, where an image of the nonexistent body part persists. However, in response to the researcher’s own assertions, extensive studies investigating the biological, pre-existing neural connections have failed to find significant results that would support the “unmasking” hypothesis Ramachandran proposed, thereby giving greater rise to the sprouting hypothesis. If such sprouting were the case, these growths would require precise and rapid cortical reorganization to enable topography to take place as well as the occurrence of complex sensations such as “gripping,” or “trickling” (Ramachandran, 1993). While this study proved to be somewhat inconclusive in that the neither of the competing hypotheses was firmly established, the rapid changes in the topographical maps implied the need for future revision of the stable or unchanging views of cortical receptive fields.

Later, Ramachandran and Rogers-Ramachandran (2000) further explored the remapping hypothesis and indeed found that unmasking of pre-existing neural connections can be referred even hours after amputation. Similar to the results in the abovementioned study, an earlier experiment on adult monkeys revealed the topographic reorganization when a stimulus was presented to a side of the face that corresponded to the hand in the cortical somatotopic map. Following this finding, magnetoencephalographic experiments showed similar results in the adult human cortex, in that the referred feelings were modality-specific (Ramachandran & Rogers-Ramachandran, 2000). For instance, sensations that were delivered to the lower face region were also felt on the phantom limb. In addition, when other parts of the body were similarly stimulated, these sensations were not as pronounced on the phantom; however, evidence showed that a second topographical map was constructed close to the missing body part. Therefore, these results provide evidence for the remapping hypothesis, where sensations occur as a result of the unmasking of pre-existing neural connections, as shown in the rapid topographical reorganization; a finding that was previously challenged (Ramachandran & Rogers- Ramachandran, 2000).

This study also highlighted the role of the conscious experience in brain activity, in that patients initially felt sensations in both the hand and the face, apparently due to the separate activation of these two regions. However, overtime the patient would begin to experience a feeling on the just the face when the hand was touched. This gives rise to a possible “cortical overshooting” during mapping reorganization, so that sensation from the hand is suppressed or masked (Ramachandran & Rogers-Ramachandaran, 2000). Finally, the researchers reported Mirror box experiments, where a patient would place the intact body part in a location that corresponded to the represented limb. Thus, the visual illusion that the phantom limb had been resurrected provided visual feedback that enabled the troubled patient to relieve any reported displeasure that had been previously experienced (Ramachandran & Rogers-Ramachandran, 2000). The importance of these studies showed the interaction between visual and somatosensory modalities, which deal with back-and-forth exchanges, rather than the initially proposed hierarchical neural model. Furthermore, these mirror image studies implied that body image is a malleable, internal construct that is also subject to change, despite its seemingly rigid and fixed appearance (Ramachandran & Rogers-Ramachandran, 2000).

==Body Image==

Body image refers to the internal and actual or idealized image that manifests itself in ways that shape an individual’s personality, self-esteem, and overall psychosocial well-being. In phantom limbs patients, the cerebral representation can be reorganized, so that the phantom is modified and sometimes even dissipated. Often times though, amputation can lead to a distorted body image that is accounted for in emotional, perceptual, and psychosocial reactions (Silvano & Reiser, 1974-1986). This sudden change not only leads to a misrepresentation of the self, but also arouses varying levels of anxiety in such patients. Additionally, denial is a common defense mechanism that cannot only result in failure to report a phantom limb, but also an inability to reorganize an individual’s body image, such that recovery and rehabilitative measures cannot be effectively taken. Consequently, this maladaptation can subsequently lead to embodiment of psychopathological characteristics, which include, but not are not limited to, depression and magical thinking (Silvano & Reiser, 1974-1986). Therefore, attempts to modify the phantom limb can only be successful depending on the relational meaning of the body part to the patient. In other words, if an amputee is unwilling to accept the present body structure, as is, this perceived defect is fully capable of interfering with motivation and recovery as a result of this disturbance (Silvano & Reiser, 1974-1986). Therefore, the unstable nature of a patient’s body image should be fully accounted for in evaluation and treatment of such patients.

==Treatment==

Successful treatment of the disturbed body image arising from the phantom limb phenomenon is dependent upon the current body of knowledge, which unfortunately, has been inadequately implemented in the present social system (Silvano & Reiser, 1974-1986). The ways in which social life is constructed can therefore profoundly affect the self-esteem, or the manner in which a patient perceives him/herself. In cases where the social structure has failed to provide supportive measures, it is vitally crucial for rehabilitative services to appropriately develop procedures that allow for ego enhancement (Silvano & Reiser, 1974-1986). The patient should be made aware of the most commonly reported phantom experiences, and fears and desires about the amputated body part should be addressed. Family, friends, and other environmental influences should also be expected to appropriately respond to such patients, for several studies have shown the detrimental effects that phantom experiences can have on body image and consequently, personality and overall psychological structure and functioning (Silvano & Reiser, 1974-1986). Therefore, these individuals should act as support systems, upon which the patient can reliably depend.

In patients who experience chronic pain, the goal of outside resources is to adopt methods of behavioral reinforcement, or operant mechanisms, which can either, prolong or reduce the individual’s expression of pain. These strategies are referred to as Fordyce’s basic principles of behavior modification (Silvano et al., 1974-1986). The approach here is to alter the patient’s behavior such that he/she can focus on engagement in other areas that enable him/her to withdraw from the reported chronic pain and exert more effortful control over these undesirable experiences. While the aforementioned suggestions regarding this phenomenon have been widely reported, the primary emphasis should remain on the reactions of amputated patients to ensure maximum recovery and restoration of a healthy body image (Silvano et al., 1974-1986).

In similar cases of chronic pain, other forms of therapy can be taken. For instance, Sympathetic Blockade refers to the intravenous infusion of guanethidine by closing off circulation. Shortly after, the patient tends to feel less pain that can sometimes result in complete recovery, but should be repeated to guarantee permanent relief (Silvano et al., 1974-1986). Other approaches to these seemingly endless periods of pain include surgical sympathectomy and chemical sympathectomy, in which destruction of the nerves in the sympathetic system can increase blood flow and reduce pain (Silvano et al., 1974-1986). Similarly, electrical stimulation, intense vibration of the stump, and injections of hypertonic saline have also shown to relieve pain, with duration of success remaining largely dependent upon the patient (Silvano et al., 1974-1986).

Finally, the abovementioned study conducted by Ramachandran and Rogers-Ramachandran (2000) confirmed the temporary, and in some cases permanent, elimination of pain in phantom limbs patients in Mirror box experiments. As previously noted, the ability to project an individual’s intact limb to a corresponding location on the mirror creates the visual illusion of the reported phantom. This visual feedback, in turn, provides these patients with the ability to relieve unwanted sensations (e.g. clenching) pertaining to the non-existent body part (Ramachandran & Rogers-Ramachandran, 2000). However, Mirror box experiments are susceptible to “placebo effects” in relation to reduction of pain, and so it is evident that studies of double-blind control subjects should be conducted. Nonetheless, whether or not this procedure produces favorable outcomes, it should still be noted that the use of visual feedback enables patients to not only see, but also feel corresponding movements in the reported phantom, which therefore gives rise to the conscious experience of this phenomenon (Ramachandran & Rogers-Ramachandran, 2000). Disturbances in an individual’s body-image and/or experience of chronic pain have been largely observed in such patients; however, the extent to which these reactions are reported provide profound implications for which therapy methods will produce the most effective results (Silvano & Reiser, 1974-1986).

==References==

Ramachandran, V. S. (1993). Behavioral and magnetoencephalographic correlates of
plasticity in the adult human brain. Proc. Natl. Acad. Sci. USA, 90, 10413-10420.

Ramachandran, V. S., & Rogers-Ramachandran, D. (2000). Phantom limbs and neural
plasticity. Archives of Neurology, 57, 317-320.

Silvano, A., & Reiser, M. F. (Eds.). (1974-1986). American handbook of psychiatry: Organic disorders and psychosomatic medicine (2nd ed., Vols. 1-8). New York, NY: Basic Books, Inc., Publishers.

Silvano, A., Berger, P. A., Keith, H., & Brodie, H. (Eds.). (1974-1986). American
handbook of psychiatry: Biological psychiatry (2nd ed., Vols. 1-8). New York, NY: Basic Books, Inc., Publishers.

Stirling, J. (2002). Introducing Neuropsychology. New York, NY: Psychology Press.

File:Phantomlimbpain.gif

Cmcfall — Sun, 27 Apr 2008 21:47:07 GMT

Cmcfall:

File:Phantomlimbs2.gif

Cmcfall — Sun, 27 Apr 2008 21:45:22 GMT

Cmcfall:

File:Phantomlimbs1.jpg

Cmcfall — Sun, 27 Apr 2008 21:45:02 GMT

Cmcfall:

Phantom limbs

Cmcfall — Sun, 27 Apr 2008 21:44:06 GMT

Cmcfall:

[[Category:Neuropsychological syndromes]]

==Overview==

Phantom limbs is a disorder of peripersonal space, in which deficits in the spatial boundary of the visual receptive fields are observed. Most notably, it refers to a sense of outstanding and often painful feeling (98% of reported cases) from an amputated body part, such as the arms or legs, which is usually most pronounced following surgery and becomes lessened overtime (Silvano, Berger, Keith, & Brodie, 1974-1986). These sensations are not limited to pain, but also include touch, temperature, wetness, and movement that arise from the no longer existent body part (Stirling, 65). It should also be noted that this phenomenon is not metaphorical in nature, but rather a sensation that is actually felt by such individuals. In fact, the realistic nature of phantom limbs is such that a patient may actually forget that a body part has been removed and attempts to use the missing limb have been widely reported (Stirling, 66). The patient also tends to exhibit a greater conscious awareness of the phantom than the opposite, intact limb (Silvano & Reiser, 1974-1986). The three most common types of the phantom are: a mild, tingling feeling; a momentary “pins and needles” sensation; and painful feelings such as “twisting,” “burning,” “itching,” and “pulling” (Silvano & Reiser, 1974-1986).

As mentioned, most individuals experience pain that can be modified or reduced via surgical procedures, but these operations have often failed to fully eliminate such displeasure (Silvano & Reiser, 1974-1986). The ineffectiveness to diminish painful phantom limb experiences was further explored as anecdotal evidence was collected to provide insight about the underlying mechanisms of this phenomenon. Moreover, case reports have shown that stimulation of body regions aligned with the cortical receptive fields adjacent to the amputated limb can elicit the phantom experience (Stirling, 66). Ramachandaran explained the effects of such experiences by proposing that sensory inputs travel to both target and neighboring regions and that normally, the adjacent regions are inhibited by direct inputs to the region. However, when these inputs are absent, commonly referred to as lateral disinhibition, the nearby regions now receive the cortical inputs, thereby evoking the phantom limb phenomenon (Stirling, 67). While Ramachandran’s assertion alone cannot account for all aspects of the experience, these findings not only highlight the need to establish methods of recovery, but they also serve as reminder that the developmental aspect of plasticity can still occur, even in mature adults (Stirling, 68).

==Neural Plasticity==

Ramachandran (1993) reported plastic changes that were observed in the visual cortex of the brain and referred to this occurrence as the “filling in” phenomenon, in which the loss of visual abilities (e.g. scotomas) caused rapid changes in the reorganization of the primary visual receptive fields. These findings led the researcher to question similar effects of other adult somatosensory pathways, including touch and hearing. Earlier studies found that after long durations of amputation, the cortical area initially corresponding to the hand was now replaced by sensory input from the ipsilateral face region. Thus, the results of these studies coupled with Ramachandran’s previous experiment generated the remapping hypothesis, which asserts the ability of the receptive fields to be temporarily expanded to proximal areas due to the “unmasking” of pre-existing neural connections, rather than the development or sprouting of new ones (Ramachandran, 1993).

Results of the study on individuals with phantom limbs, revealed a one-to-one correspondence between points on the patient’s fingers as well as on the face, which were not randomly represented, but observed on the lower face region and the area near deafferentation (Ramachandran, 1993). Additionally, it was further suggested that complex sensations distal from the region of amputation could be referred, which occur at a rapid rate of reorganization. Thus, modality-specific “rewiring” can effectively occur even after short periods of stimulus deprivation, thereby supporting Ramachandran’s hypothesis that phantom limb experience arises from spontaneous activity of tissues in the face and those near the amputated limb (Ramachandran, 1993). It was also thought that reafferance signals are combined with motor commands that are then sent to the muscle(s) of the phantom limb and to some degree, from neuromas, or tumors that are comprised of nerve tissues (Ramachandran, 1993). The information from these sources is lastly processed in the parietal cortex, which gives rise to the experience, where an image of the nonexistent body part persists. However, in response to the researcher’s own assertions, extensive studies investigating the biological, pre-existing neural connections have failed to find significant results that would support the “unmasking” hypothesis Ramachandran proposed, thereby giving greater rise to the sprouting hypothesis. If such sprouting were the case, these growths would require precise and rapid cortical reorganization to enable topography to take place as well as the occurrence of complex sensations such as “gripping,” or “trickling” (Ramachandran, 1993). While this study proved to be somewhat inconclusive in that the neither of the competing hypotheses was firmly established, the rapid changes in the topographical maps implied the need for future revision of the stable or unchanging views of cortical receptive fields.

Later, Ramachandran and Rogers-Ramachandran (2000) further explored the remapping hypothesis and indeed found that unmasking of pre-existing neural connections can be referred even hours after amputation. Similar to the results in the abovementioned study, an earlier experiment on adult monkeys revealed the topographic reorganization when a stimulus was presented to a side of the face that corresponded to the hand in the cortical somatotopic map. Following this finding, magnetoencephalographic experiments showed similar results in the adult human cortex, in that the referred feelings were modality-specific (Ramachandran & Rogers-Ramachandran, 2000). For instance, sensations that were delivered to the lower face region were also felt on the phantom limb. In addition, when other parts of the body were similarly stimulated, these sensations were not as pronounced on the phantom; however, evidence showed that a second topographical map was constructed close to the missing body part. Therefore, these results provide evidence for the remapping hypothesis, where sensations occur as a result of the unmasking of pre-existing neural connections, as shown in the rapid topographical reorganization; a finding that was previously challenged (Ramachandran & Rogers- Ramachandran, 2000).

This study also highlighted the role of the conscious experience in brain activity, in that patients initially felt sensations in both the hand and the face, apparently due to the separate activation of these two regions. However, overtime the patient would begin to experience a feeling on the just the face when the hand was touched. This gives rise to a possible “cortical overshooting” during mapping reorganization, so that sensation from the hand is suppressed or masked (Ramachandran & Rogers-Ramachandaran, 2000). Finally, the researchers reported Mirror box experiments, where a patient would place the intact body part in a location that corresponded to the represented limb. Thus, the visual illusion that the phantom limb had been resurrected provided visual feedback that enabled the troubled patient to relieve any reported displeasure that had been previously experienced (Ramachandran & Rogers-Ramachandran, 2000). The importance of these studies showed the interaction between visual and somatosensory modalities, which deal with back-and-forth exchanges, rather than the initially proposed hierarchical neural model. Furthermore, these mirror image studies implied that body image is a malleable, internal construct that is also subject to change, despite its seemingly rigid and fixed appearance (Ramachandran & Rogers-Ramachandran, 2000).

==Body Image==

Body image refers to the internal and actual or idealized image that manifests itself in ways that shape an individual’s personality, self-esteem, and overall psychosocial well-being. In phantom limbs patients, the cerebral representation can be reorganized, so that the phantom is modified and sometimes even dissipated. Often times though, amputation can lead to a distorted body image that is accounted for in emotional, perceptual, and psychosocial reactions (Silvano & Reiser, 1974-1986). This sudden change not only leads to a misrepresentation of the self, but also arouses varying levels of anxiety in such patients. Additionally, denial is a common defense mechanism that cannot only result in failure to report a phantom limb, but also an inability to reorganize an individual’s body image, such that recovery and rehabilitative measures cannot be effectively taken. Consequently, this maladaptation can subsequently lead to embodiment of psychopathological characteristics, which include, but not are not limited to, depression and magical thinking (Silvano & Reiser, 1974-1986). Therefore, attempts to modify the phantom limb can only be successful depending on the relational meaning of the body part to the patient. In other words, if an amputee is unwilling to accept the present body structure, as is, this perceived defect is fully capable of interfering with motivation and recovery as a result of this disturbance (Silvano & Reiser, 1974-1986). Therefore, the unstable nature of a patient’s body image should be fully accounted for in evaluation and treatment of such patients.

==Treatment==

Successful treatment of the disturbed body image arising from the phantom limb phenomenon is dependent upon the current body of knowledge, which unfortunately, has been inadequately implemented in the present social system (Silvano & Reiser, 1974-1986). The ways in which social life is constructed can therefore profoundly affect the self-esteem, or the manner in which a patient perceives him/herself. In cases where the social structure has failed to provide supportive measures, it is vitally crucial for rehabilitative services to appropriately develop procedures that allow for ego enhancement (Silvano & Reiser, 1974-1986). The patient should be made aware of the most commonly reported phantom experiences, and fears and desires about the amputated body part should be addressed. Family, friends, and other environmental influences should also be expected to appropriately respond to such patients, for several studies have shown the detrimental effects that phantom experiences can have on body image and consequently, personality and overall psychological structure and functioning (Silvano & Reiser, 1974-1986). Therefore, these individuals should act as support systems, upon which the patient can reliably depend.

In patients who experience chronic pain, the goal of outside resources is to adopt methods of behavioral reinforcement, or operant mechanisms, which can either, prolong or reduce the individual’s expression of pain. These strategies are referred to as Fordyce’s basic principles of behavior modification (Silvano et al., 1974-1986). The approach here is to alter the patient’s behavior such that he/she can focus on engagement in other areas that enable him/her to withdraw from the reported chronic pain and exert more effortful control over these undesirable experiences. While the aforementioned suggestions regarding this phenomenon have been widely reported, the primary emphasis should remain on the reactions of amputated patients to ensure maximum recovery and restoration of a healthy body image (Silvano et al., 1974-1986).

In similar cases of chronic pain, other forms of therapy can be taken. For instance, Sympathetic Blockade refers to the intravenous infusion of guanethidine by closing off circulation. Shortly after, the patient tends to feel less pain that can sometimes result in complete recovery, but should be repeated to guarantee permanent relief (Silvano et al., 1974-1986). Other approaches to these seemingly endless periods of pain include surgical sympathectomy and chemical sympathectomy, in which destruction of the nerves in the sympathetic system can increase blood flow and reduce pain (Silvano et al., 1974-1986). Similarly, electrical stimulation, intense vibration of the stump, and injections of hypertonic saline have also shown to relieve pain, with duration of success remaining largely dependent upon the patient (Silvano et al., 1974-1986).

Finally, the abovementioned study conducted by Ramachandran and Rogers-Ramachandran (2000) confirmed the temporary, and in some cases permanent, elimination of pain in phantom limbs patients in Mirror box experiments. As previously noted, the ability to project an individual’s intact limb to a corresponding location on the mirror creates the visual illusion of the reported phantom. This visual feedback, in turn, provides these patients with the ability to relieve unwanted sensations (e.g. clenching) pertaining to the non-existent body part (Ramachandran & Rogers-Ramachandran, 2000). However, Mirror box experiments are susceptible to “placebo effects” in relation to reduction of pain, and so it is evident that studies of double-blind control subjects should be conducted. Nonetheless, whether or not this procedure produces favorable outcomes, it should still be noted that the use of visual feedback enables patients to not only see, but also feel corresponding movements in the reported phantom, which therefore gives rise to the conscious experience of this phenomenon (Ramachandran & Rogers-Ramachandran, 2000). Disturbances in an individual’s body-image and/or experience of chronic pain have been largely observed in such patients; however, the extent to which these reactions are reported provide profound implications for which therapy methods will produce the most effective results (Silvano & Reiser, 1974-1986).

==References==

Ramachandran, V. S. (1993). Behavioral and magnetoencephalographic correlates of
plasticity in the adult human brain. Proc. Natl. Acad. Sci. USA, 90, 10413-10420.

Ramachandran, V. S., & Rogers-Ramachandran, D. (2000). Phantom limbs and neural
plasticity. Archives of Neurology, 57, 317-320.

Silvano, A., & Reiser, M. F. (Eds.). (1974-1986). American handbook of psychiatry: Organic disorders and psychosomatic medicine (2nd ed., Vols. 1-8). New York, NY: Basic Books, Inc., Publishers.

Silvano, A., Berger, P. A., Keith, H., & Brodie, H. (Eds.). (1974-1986). American
handbook of psychiatry: Biological psychiatry (2nd ed., Vols. 1-8). New York, NY: Basic Books, Inc., Publishers.

Stirling, J. (2002). Introducing Neuropsychology. New York, NY: Psychology Press.

Amygdala

Cmcfall — Sun, 27 Apr 2008 21:40:54 GMT

Cmcfall:

[[Category:Brain areas]]

==Overview==

The amygdala represents an anatomical structure of the brain that is involved in a range of behavioral and mental conditions (LeDoux, 2007). Previously, this area had received little scientific recognition, but now it is one of the most extensively studied brain regions. The name “amygdala” is rooted in Greek and refers to the almond-shaped structure located bilaterally within the temporal lobes of the limbic system (LeDoux, 2007). Most individuals assume the amygdala to be comprised of a single mass; however, its composition includes several nuclei, which can be found in species of higher cognitive functioning, including humans and primates. Consistent with this view, it can be argued that the amygdala is not a unitary structure or function, but rather accords several regions that contribute to cognitive functions of other areas in the brain (LeDoux, 2007). In specific, the lateral and basal amygdala are viewed as nuclear extensions of the cortex, while the central and medial nuclei are part of ventral expansions of the striatum and each of these areas can further be divided into subnuclei, which are all relevant to the study of this anatomical region. For example, the dorsal subcomponent of the lateral nucleus is said to be involved in varying aspects of fear memory (LeDoux, 2007).

[[Image:Amygdala-hippocampus.jpg]]

==Connectivity==

The importance of connectivity points to the ability for specific areas of the brain to make connections with other related regions for the purpose of function (LeDoux, 2007). For instance, the lateral amygdala is responsible for receiving stimulatory input from different sensory systems, such as the visual, somatosensory, olfactory, and auditory modalities (LeDoux, 2007). These inputs are then transferred and consummated in the dorsal subnucleus. This subregion then relays information to the ventrolateral and medial areas in order to connect with other areas of the amygdala (LeDoux, 2007).
The region most notable in behavioral and physiological output is the central nucleus, in which connections from the medial subarea and other interconnected nuclei (e.g. basal nucleus) are involved, at least for the expression of emotional responses. As previously mentioned, areas in the striatum also connect with the central nucleus in instrumental behaviors (LeDoux, 2007). More specifically, sensory output from the central amygdala to the brainstem results in the management of emotions, but the interconnectivity between the basal subregion and the striatum are responsible for controlling action-based behaviors, like running from a potential marauder. Finally, the extent to which the connections are successful in relaying communication relies on the role of various neurotransmitter systems, such as dopamine and serotonin, thereby resulting in exhibitory and inhibitory behavioral responses (LeDoux, 2007).

==Behavior==

In the early 20th century, observed damage in the temporal lobe showed profound changes in behaviors such as fear and sex-related responses (LeDoux, 2007). After determining that the amygdala played a role in these impairments, the inability to account for the underlying substructures of this area resulted in a body of research that was widely misunderstood. It was not until after the discovery of the amygdala’s subcomponents, in which researchers were able to study specific behavioral functions associated with this region (LeDoux, 2007).

'''Fear'''

Fear has been documented throughout scientific literature and more specifically, use of Pavlovian conditioning (the seemingly innate ability to learn stimulus-response (SR) affiliations when presented with associative stimuli) has been shown to consistently and effectively measure such behavior (LeDoux, 2007). The habituation of these associations, through prolonged exposure, implies the developmental aspect of plasticity to aid in the maintenance of short-term memory. Moreover, when these SR associations are re-presented to an individual, the enduring plasticity reveals storage of the appropriate information to the individual’s long-term memory (LeDoux, 2007). While fear response continues to be the most salient behavioral function associated with the amygdala, other research has pointed out that this region is also involved in other emotions such as aggression, sexuality, and addictive, ingestive behaviors (e.g. eating and drinking). Additionally, the amygdala’s ability to release hormones, through neurotransmitter modalities, to other regions of the brain also influences other specific types of cognition, such as attention, perception, and explicit memory (LeDoux, 2007). In other words, the amygdala’s emotional processing to external stimuli establishes connections with other functions of the brain. As earlier noted, the amygdala plays a role in several psychiatric conditions, like autism, schizophrenia, borderline personality disorder, and depression. More importantly, the amygdala is not the cause of these disorders, but rather alterations in the representation of this region result in specific behavioral changes in these individuals (LeDoux, 2007).

[[Image:Amygdalafear.jpg]]

'''Relevant Studies'''

Bechara, Tranel, Damasio, Adolphs, Rockland, and Damasio (1995) studied the double dissociation between conditioning and declarative knowledge in relation to the amygdala and the hippocampus in three patients. In two conditioning experiments, using a skin conductance response (SCR) measure, the researchers found that the patient with bilateral damage to the amygdala was unable to acquire the conditioned autonomic responses to the presented visual or auditory stimuli; however, declarative knowledge of the stimuli was largely spared (Bechara et al., 1995). Conversely, the patient with hippocampal damage was able to acquire the conditioned autonomic responses, but failed to retain declarative knowledge of the material. Lastly, the third patient had damage to both brain areas, resulting in an inability to acquire both conditioned autonomic responses and declarative facts. Consistent with previous research, this study further suggested the role the amygdala plays in associative cues of affect, while the hippocampus is responsible for learning the critical relationships among these cues (Bechara et al., 1995).

A later study conducted by Bechara, Damasio, Damasio, and Lee (1999) focused on the contributions of the amygdala and the ventromedial prefrontal (VMF) cortex in human decision-making. Using the “gambling task” to measure decision-making and a skin conductance response (SCR) instrument, the researchers were able to effectively study a group of patients with bilateral amygdala damage and another group with VMF bilateral damage (Bechara et al., 1999). In a Pavlovian conditioning experiment, participants were also tested for acquisition of a conditioned SCR to paired visual stimuli and an aversive loud noise (Bechara et al., 1999). Results of the study revealed that the two areas have distinct influences on decision-making. More specifically, patients with amygdala damage were unable to produce SCRs on both the “gambling task” as well as the conditioning experiment. The group of individuals with VMF damage were also unable to generate SCRs on the “gambling task,” but were able to produce a response when presented with a reward or punishment (e.g. play money), while the amygdala-damaged patients still failed to produce such a response when they received similar reinforcements (Bechara et al., 1999). The differences associated with decision-making in the two groups implies potentially bigger consequences for the patients with bilateral amygdala damage, in that the failure to evoke the appropriate somatic state results in impairment of future decision-making tasks that elicit similar somatic affects (Bechara, 1999). In sum, this study paralleled earlier research about the underlying functions of the orbitofrontal cortex and the basolateral amygdala and their association with goal-directed behavior. While both groups of patients showed impairments on similar decision-making tasks, the individuals with bilateral damage to the amygdala are much more susceptible to both psychologically and physically harmful real-life situations, where a decision may be critical (Bechara, 1999). In other words, their overall failure to adequately respond to external stimuli due to alterations in emotional states (e.g. fear), may therefore cause such individuals to choose a course of action, in which an unfavorable outcome could result in devastating mental and/or physical consequences.

'''Interesting fact'''

The amygdala is responsible for the emotional reactions to music.

==References==

Bechara, A., Tranel, D., Damasio, H., Adolphs, R., Rockland, C., & Damasio, A. R.
(1995). Double dissociation of conditioning and declarative knowledge relative
to the amygdala and hippocampus in humans. Science, 269, 1115-1118.

Bechara, A., Damasio, H., Damasio, A. R., & Lee, G. P. (1999). Different contributions
of the human amygdala and ventromedial prefrontal cortex to decision-making.
The Journal of Neuroscience, 19(3), 5473-5481.

LeDoux, J. (2007). The amygdala. Current Biology, 17, 868-874.

Amygdala

Cmcfall — Sun, 27 Apr 2008 21:40:01 GMT

Cmcfall:

[[Category:Brain areas]]

==Overview==

The amygdala represents an anatomical structure of the brain that is involved in a range of behavioral and mental conditions (LeDoux, 2007). Previously, this area had received little scientific recognition, but now it is one of the most extensively studied brain regions. The name “amygdala” is rooted in Greek and refers to the almond-shaped structure located bilaterally within the temporal lobes of the limbic system (LeDoux, 2007). Most individuals assume the amygdala to be comprised of a single mass; however, its composition includes several nuclei, which can be found in species of higher cognitive functioning, including humans and primates. Consistent with this view, it can be argued that the amygdala is not a unitary structure or function, but rather accords several regions that contribute to cognitive functions of other areas in the brain (LeDoux, 2007). In specific, the lateral and basal amygdala are viewed as nuclear extensions of the cortex, while the central and medial nuclei are part of ventral expansions of the striatum and each of these areas can further be divided into subnuclei, which are all relevant to the study of this anatomical region. For example, the dorsal subcomponent of the lateral nucleus is said to be involved in varying aspects of fear memory (LeDoux, 2007).

[[Image:Amygdala-hippocampus.jpg]]

==Connectivity==

The importance of connectivity points to the ability for specific areas of the brain to make connections with other related regions for the purpose of function (LeDoux, 2007). For instance, the lateral amygdala is responsible for receiving stimulatory input from different sensory systems, such as the visual, somatosensory, olfactory, and auditory modalities (LeDoux, 2007). These inputs are then transferred and consummated in the dorsal subnucleus. This subregion then relays information to the ventrolateral and medial areas in order to connect with other areas of the amygdala (LeDoux, 2007).
The region most notable in behavioral and physiological output is the central nucleus, in which connections from the medial subarea and other interconnected nuclei (e.g. basal nucleus) are involved, at least for the expression of emotional responses. As previously mentioned, areas in the striatum also connect with the central nucleus in instrumental behaviors (LeDoux, 2007). More specifically, sensory output from the central amygdala to the brainstem results in the management of emotions, but the interconnectivity between the basal subregion and the striatum are responsible for controlling action-based behaviors, like running from a potential marauder. Finally, the extent to which the connections are successful in relaying communication relies on the role of various neurotransmitter systems, such as dopamine and serotonin, thereby resulting in exhibitory and inhibitory behavioral responses (LeDoux, 2007).

==Behavior==

In the early 20th century, observed damage in the temporal lobe showed profound changes in behaviors such as fear and sex-related responses (LeDoux, 2007). After determining that the amygdala played a role in these impairments, the inability to account for the underlying substructures of this area resulted in a body of research that was widely misunderstood. It was not until after the discovery of the amygdala’s subcomponents, in which researchers were able to study specific behavioral functions associated with this region (LeDoux, 2007).

'''Fear'''

Fear has been documented throughout scientific literature and more specifically, use of Pavlovian conditioning (the seemingly innate ability to learn stimulus-response (SR) affiliations when presented with associative stimuli) has been shown to consistently and effectively measure such behavior (LeDoux, 2007). The habituation of these associations, through prolonged exposure, implies the developmental aspect of plasticity to aid in the maintenance of short-term memory. Moreover, when these SR associations are re-presented to an individual, the enduring plasticity reveals storage of the appropriate information to the individual’s long-term memory (LeDoux, 2007). While fear response continues to be the most salient behavioral function associated with the amygdala, other research has pointed out that this region is also involved in other emotions such as aggression, sexuality, and addictive, ingestive behaviors (e.g. eating and drinking). Additionally, the amygdala’s ability to release hormones, through neurotransmitter modalities, to other regions of the brain also influences other specific types of cognition, such as attention, perception, and explicit memory (LeDoux, 2007). In other words, the amygdala’s emotional processing to external stimuli establishes connections with other functions of the brain. As earlier noted, the amygdala plays a role in several psychiatric conditions, like autism, schizophrenia, borderline personality disorder, and depression. More importantly, the amygdala is not the cause of these disorders, but rather alterations in the representation of this region result in specific behavioral changes in these individuals (LeDoux, 2007).

[[Image:Amygdalafear.jpg]]

'''Relevant Studies'''

Bechara, Tranel, Damasio, Adolphs, Rockland, and Damasio (1995) studied the double dissociation between conditioning and declarative knowledge in relation to the amygdala and the hippocampus in three patients. In two conditioning experiments, using a skin conductance response (SCR) measure, the researchers found that the patient with bilateral damage to the amygdala was unable to acquire the conditioned autonomic responses to the presented visual or auditory stimuli; however, declarative knowledge of the stimuli was largely spared (Bechara et al., 1995). Conversely, the patient with hippocampal damage was able to acquire the conditioned autonomic responses, but failed to retain declarative knowledge of the material. Lastly, the third patient had damage to both brain areas, resulting in an inability to acquire both conditioned autonomic responses and declarative facts. Consistent with previous research, this study further suggested the role the amygdala plays in associative cues of affect, while the hippocampus is responsible for learning the critical relationships among these cues (Bechara et al., 1995).
A later study conducted by Bechara, Damasio, Damasio, and Lee (1999) focused on the contributions of the amygdala and the ventromedial prefrontal (VMF) cortex in human decision-making. Using the “gambling task” to measure decision-making and a skin conductance response (SCR) instrument, the researchers were able to effectively study a group of patients with bilateral amygdala damage and another group with VMF bilateral damage (Bechara et al., 1999). In a Pavlovian conditioning experiment, participants were also tested for acquisition of a conditioned SCR to paired visual stimuli and an aversive loud noise (Bechara et al., 1999). Results of the study revealed that the two areas have distinct influences on decision-making. More specifically, patients with amygdala damage were unable to produce SCRs on both the “gambling task” as well as the conditioning experiment. The group of individuals with VMF damage were also unable to generate SCRs on the “gambling task,” but were able to produce a response when presented with a reward or punishment (e.g. play money), while the amygdala-damaged patients still failed to produce such a response when they received similar reinforcements (Bechara et al., 1999).
The differences associated with decision-making in the two groups implies potentially bigger consequences for the patients with bilateral amygdala damage, in that the failure to evoke the appropriate somatic state results in impairment of future decision-making tasks that elicit similar somatic affects (Bechara, 1999). In sum, this study paralleled earlier research about the underlying functions of the orbitofrontal cortex and the basolateral amygdala and their association with goal-directed behavior. While both groups of patients showed impairments on similar decision-making tasks, the individuals with bilateral damage to the amygdala are much more susceptible to both psychologically and physically harmful real-life situations, where a decision may be critical (Bechara, 1999). In other words, their overall failure to adequately respond to external stimuli due to alterations in emotional states (e.g. fear), may therefore cause such individuals to choose a course of action, in which an unfavorable outcome could result in devastating mental and/or physical consequences.

'''Interesting fact'''

The amygdala is responsible for the emotional reactions to music.

==References==

Bechara, A., Tranel, D., Damasio, H., Adolphs, R., Rockland, C., & Damasio, A. R.
(1995). Double dissociation of conditioning and declarative knowledge relative
to the amygdala and hippocampus in humans. Science, 269, 1115-1118.

Bechara, A., Damasio, H., Damasio, A. R., & Lee, G. P. (1999). Different contributions
of the human amygdala and ventromedial prefrontal cortex to decision-making.
The Journal of Neuroscience, 19(3), 5473-5481.

LeDoux, J. (2007). The amygdala. Current Biology, 17, 868-874.

File:Amygdalafear.jpg

Cmcfall — Sun, 27 Apr 2008 21:38:52 GMT

Cmcfall:

Amygdala

Cmcfall — Sun, 27 Apr 2008 21:38:14 GMT

Cmcfall:

[[Category:Brain areas]]

==Overview==

The amygdala represents an anatomical structure of the brain that is involved in a range of behavioral and mental conditions (LeDoux, 2007). Previously, this area had received little scientific recognition, but now it is one of the most extensively studied brain regions. The name “amygdala” is rooted in Greek and refers to the almond-shaped structure located bilaterally within the temporal lobes of the limbic system (LeDoux, 2007). Most individuals assume the amygdala to be comprised of a single mass; however, its composition includes several nuclei, which can be found in species of higher cognitive functioning, including humans and primates. Consistent with this view, it can be argued that the amygdala is not a unitary structure or function, but rather accords several regions that contribute to cognitive functions of other areas in the brain (LeDoux, 2007). In specific, the lateral and basal amygdala are viewed as nuclear extensions of the cortex, while the central and medial nuclei are part of ventral expansions of the striatum and each of these areas can further be divided into subnuclei, which are all relevant to the study of this anatomical region. For example, the dorsal subcomponent of the lateral nucleus is said to be involved in varying aspects of fear memory (LeDoux, 2007).

[[Image:Amygdala-hippocampus.jpg]]

==Connectivity==

The importance of connectivity points to the ability for specific areas of the brain to make connections with other related regions for the purpose of function (LeDoux, 2007). For instance, the lateral amygdala is responsible for receiving stimulatory input from different sensory systems, such as the visual, somatosensory, olfactory, and auditory modalities (LeDoux, 2007). These inputs are then transferred and consummated in the dorsal subnucleus. This subregion then relays information to the ventrolateral and medial areas in order to connect with other areas of the amygdala (LeDoux, 2007).
The region most notable in behavioral and physiological output is the central nucleus, in which connections from the medial subarea and other interconnected nuclei (e.g. basal nucleus) are involved, at least for the expression of emotional responses. As previously mentioned, areas in the striatum also connect with the central nucleus in instrumental behaviors (LeDoux, 2007). More specifically, sensory output from the central amygdala to the brainstem results in the management of emotions, but the interconnectivity between the basal subregion and the striatum are responsible for controlling action-based behaviors, like running from a potential marauder. Finally, the extent to which the connections are successful in relaying communication relies on the role of various neurotransmitter systems, such as dopamine and serotonin, thereby resulting in exhibitory and inhibitory behavioral responses (LeDoux, 2007).

==Behavior==

In the early 20th century, observed damage in the temporal lobe showed profound changes in behaviors such as fear and sex-related responses (LeDoux, 2007). After determining that the amygdala played a role in these impairments, the inability to account for the underlying substructures of this area resulted in a body of research that was widely misunderstood. It was not until after the discovery of the amygdala’s subcomponents, in which researchers were able to study specific behavioral functions associated with this region (LeDoux, 2007).

'''Fear'''

Fear has been documented throughout scientific literature and more specifically, use of Pavlovian conditioning (the seemingly innate ability to learn stimulus-response (SR) affiliations when presented with associative stimuli) has been shown to consistently and effectively measure such behavior (LeDoux, 2007). The habituation of these associations, through prolonged exposure, implies the developmental aspect of plasticity to aid in the maintenance of short-term memory. Moreover, when these SR associations are re-presented to an individual, the enduring plasticity reveals storage of the appropriate information to the individual’s long-term memory (LeDoux, 2007). While fear response continues to be the most salient behavioral function associated with the amygdala, other research has pointed out that this region is also involved in other emotions such as aggression, sexuality, and addictive, ingestive behaviors (e.g. eating and drinking). Additionally, the amygdala’s ability to release hormones, through neurotransmitter modalities, to other regions of the brain also influences other specific types of cognition, such as attention, perception, and explicit memory (LeDoux, 2007). In other words, the amygdala’s emotional processing to external stimuli establishes connections with other functions of the brain. As earlier noted, the amygdala plays a role in several psychiatric conditions, like autism, schizophrenia, borderline personality disorder, and depression. More importantly, the amygdala is not the cause of these disorders, but rather alterations in the representation of this region result in specific behavioral changes in these individuals (LeDoux, 2007).

'''Relevant Studies'''

Bechara, Tranel, Damasio, Adolphs, Rockland, and Damasio (1995) studied the double dissociation between conditioning and declarative knowledge in relation to the amygdala and the hippocampus in three patients. In two conditioning experiments, using a skin conductance response (SCR) measure, the researchers found that the patient with bilateral damage to the amygdala was unable to acquire the conditioned autonomic responses to the presented visual or auditory stimuli; however, declarative knowledge of the stimuli was largely spared (Bechara et al., 1995). Conversely, the patient with hippocampal damage was able to acquire the conditioned autonomic responses, but failed to retain declarative knowledge of the material. Lastly, the third patient had damage to both brain areas, resulting in an inability to acquire both conditioned autonomic responses and declarative facts. Consistent with previous research, this study further suggested the role the amygdala plays in associative cues of affect, while the hippocampus is responsible for learning the critical relationships among these cues (Bechara et al., 1995).
A later study conducted by Bechara, Damasio, Damasio, and Lee (1999) focused on the contributions of the amygdala and the ventromedial prefrontal (VMF) cortex in human decision-making. Using the “gambling task” to measure decision-making and a skin conductance response (SCR) instrument, the researchers were able to effectively study a group of patients with bilateral amygdala damage and another group with VMF bilateral damage (Bechara et al., 1999). In a Pavlovian conditioning experiment, participants were also tested for acquisition of a conditioned SCR to paired visual stimuli and an aversive loud noise (Bechara et al., 1999). Results of the study revealed that the two areas have distinct influences on decision-making. More specifically, patients with amygdala damage were unable to produce SCRs on both the “gambling task” as well as the conditioning experiment. The group of individuals with VMF damage were also unable to generate SCRs on the “gambling task,” but were able to produce a response when presented with a reward or punishment (e.g. play money), while the amygdala-damaged patients still failed to produce such a response when they received similar reinforcements (Bechara et al., 1999).
The differences associated with decision-making in the two groups implies potentially bigger consequences for the patients with bilateral amygdala damage, in that the failure to evoke the appropriate somatic state results in impairment of future decision-making tasks that elicit similar somatic affects (Bechara, 1999). In sum, this study paralleled earlier research about the underlying functions of the orbitofrontal cortex and the basolateral amygdala and their association with goal-directed behavior. While both groups of patients showed impairments on similar decision-making tasks, the individuals with bilateral damage to the amygdala are much more susceptible to both psychologically and physically harmful real-life situations, where a decision may be critical (Bechara, 1999). In other words, their overall failure to adequately respond to external stimuli due to alterations in emotional states (e.g. fear), may therefore cause such individuals to choose a course of action, in which an unfavorable outcome could result in devastating mental and/or physical consequences.

'''Interesting fact'''

The amygdala is responsible for the emotional reactions to music.

==References==

Bechara, A., Tranel, D., Damasio, H., Adolphs, R., Rockland, C., & Damasio, A. R.
(1995). Double dissociation of conditioning and declarative knowledge relative
to the amygdala and hippocampus in humans. Science, 269, 1115-1118.

Bechara, A., Damasio, H., Damasio, A. R., & Lee, G. P. (1999). Different contributions
of the human amygdala and ventromedial prefrontal cortex to decision-making.
The Journal of Neuroscience, 19(3), 5473-5481.

LeDoux, J. (2007). The amygdala. Current Biology, 17, 868-874.

Amygdala

Cmcfall — Sun, 27 Apr 2008 21:37:21 GMT

Cmcfall:

[[Category:Brain areas]]

==Overview==

The amygdala represents an anatomical structure of the brain that is involved in a range of behavioral and mental conditions (LeDoux, 2007). Previously, this area had received little scientific recognition, but now it is one of the most extensively studied brain regions. The name “amygdala” is rooted in Greek and refers to the almond-shaped structure located bilaterally within the temporal lobes of the limbic system (LeDoux, 2007). Most individuals assume the amygdala to be comprised of a single mass; however, its composition includes several nuclei, which can be found in species of higher cognitive functioning, including humans and primates. Consistent with this view, it can be argued that the amygdala is not a unitary structure or function, but rather accords several regions that contribute to cognitive functions of other areas in the brain (LeDoux, 2007). In specific, the lateral and basal amygdala are viewed as nuclear extensions of the cortex, while the central and medial nuclei are part of ventral expansions of the striatum and each of these areas can further be divided into subnuclei, which are all relevant to the study of this anatomical region. For example, the dorsal subcomponent of the lateral nucleus is said to be involved in varying aspects of fear memory (LeDoux, 2007).

[[Image:Amygdala-hippocampus.jpg]]

==Connectivity==

The importance of connectivity points to the ability for specific areas of the brain to make connections with other related regions for the purpose of function (LeDoux, 2007). For instance, the lateral amygdala is responsible for receiving stimulatory input from different sensory systems, such as the visual, somatosensory, olfactory, and auditory modalities (LeDoux, 2007). These inputs are then transferred and consummated in the dorsal subnucleus. This subregion then relays information to the ventrolateral and medial areas in order to connect with other areas of the amygdala (LeDoux, 2007).
The region most notable in behavioral and physiological output is the central nucleus, in which connections from the medial subarea and other interconnected nuclei (e.g. basal nucleus) are involved, at least for the expression of emotional responses. As previously mentioned, areas in the striatum also connect with the central nucleus in instrumental behaviors (LeDoux, 2007). More specifically, sensory output from the central amygdala to the brainstem results in the management of emotions, but the interconnectivity between the basal subregion and the striatum are responsible for controlling action-based behaviors, like running from a potential marauder. Finally, the extent to which the connections are successful in relaying communication relies on the role of various neurotransmitter systems, such as dopamine and serotonin, thereby resulting in exhibitory and inhibitory behavioral responses (LeDoux, 2007).

==Behavior==

In the early 20th century, observed damage in the temporal lobe showed profound changes in behaviors such as fear and sex-related responses (LeDoux, 2007). After determining that the amygdala played a role in these impairments, the inability to account for the underlying substructures of this area resulted in a body of research that was widely misunderstood. It was not until after the discovery of the amygdala’s subcomponents, in which researchers were able to study specific behavioral functions associated with this region (LeDoux, 2007).

'''Fear'''

Fear has been documented throughout scientific literature and more specifically, use of Pavlovian conditioning (the seemingly innate ability to learn stimulus-response (SR) affiliations when presented with associative stimuli) has been shown to consistently and effectively measure such behavior (LeDoux, 2007). The habituation of these associations, through prolonged exposure, implies the developmental aspect of plasticity to aid in the maintenance of short-term memory. Moreover, when these SR associations are re-presented to an individual, the enduring plasticity reveals storage of the appropriate information to the individual’s long-term memory (LeDoux, 2007). While fear response continues to be the most salient behavioral function associated with the amygdala, other research has pointed out that this region is also involved in other emotions such as aggression, sexuality, and addictive, ingestive behaviors (e.g. eating and drinking). Additionally, the amygdala’s ability to release hormones, through neurotransmitter modalities, to other regions of the brain also influences other specific types of cognition, such as attention, perception, and explicit memory (LeDoux, 2007). In other words, the amygdala’s emotional processing to external stimuli establishes connections with other functions of the brain. As earlier noted, the amygdala plays a role in several psychiatric conditions, like autism, schizophrenia, borderline personality disorder, and depression. More importantly, the amygdala is not the cause of these disorders, but rather alterations in the representation of this region result in specific behavioral changes in these individuals (LeDoux, 2007).

'''Relevant Studies'''

Bechara, Tranel, Damasio, Adolphs, Rockland, and Damasio (1995) studied the double dissociation between conditioning and declarative knowledge in relation to the amygdala and the hippocampus in three patients. In two conditioning experiments, using a skin conductance response (SCR) measure, the researchers found that the patient with bilateral damage to the amygdala was unable to acquire the conditioned autonomic responses to the presented visual or auditory stimuli; however, declarative knowledge of the stimuli was largely spared (Bechara et al., 1995). Conversely, the patient with hippocampal damage was able to acquire the conditioned autonomic responses, but failed to retain declarative knowledge of the material. Lastly, the third patient had damage to both brain areas, resulting in an inability to acquire both conditioned autonomic responses and declarative facts. Consistent with previous research, this study further suggested the role the amygdala plays in associative cues of affect, while the hippocampus is responsible for learning the critical relationships among these cues (Bechara et al., 1995).
A later study conducted by Bechara, Damasio, Damasio, and Lee (1999) focused on the contributions of the amygdala and the ventromedial prefrontal (VMF) cortex in human decision-making. Using the “gambling task” to measure decision-making and a skin conductance response (SCR) instrument, the researchers were able to effectively study a group of patients with bilateral amygdala damage and another group with VMF bilateral damage (Bechara et al., 1999). In a Pavlovian conditioning experiment, participants were also tested for acquisition of a conditioned SCR to paired visual stimuli and an aversive loud noise (Bechara et al., 1999). Results of the study revealed that the two areas have distinct influences on decision-making. More specifically, patients with amygdala damage were unable to produce SCRs on both the “gambling task” as well as the conditioning experiment. The group of individuals with VMF damage were also unable to generate SCRs on the “gambling task,” but were able to produce a response when presented with a reward or punishment (e.g. play money), while the amygdala-damaged patients still failed to produce such a response when they received similar reinforcements (Bechara et al., 1999).
The differences associated with decision-making in the two groups implies potentially bigger consequences for the patients with bilateral amygdala damage, in that the failure to evoke the appropriate somatic state results in impairment of future decision-making tasks that elicit similar somatic affects (Bechara, 1999). In sum, this study paralleled earlier research about the underlying functions of the orbitofrontal cortex and the basolateral amygdala and their association with goal-directed behavior. While both groups of patients showed impairments on similar decision-making tasks, the individuals with bilateral damage to the amygdala are much more susceptible to both psychologically and physically harmful real-life situations, where a decision may be critical (Bechara, 1999). In other words, their overall failure to adequately respond to external stimuli due to alterations in emotional states (e.g. fear), may therefore cause such individuals to choose a course of action, in which an unfavorable outcome could result in devastating mental and/or physical consequences.

'''Interesting fact'''

The amygdala is responsible for the emotional reactions to music.

==References==

Bechara, A., Tranel, D., Damasio, H., Adolphs, R., Rockland, C., & Damasio, A. R.
(1995). Double dissociation of conditioning and declarative knowledge relative
to the amygdala and hippocampus in humans. Science, 269, 1115-1118.

Bechara, A., Damasio, H., Damasio, A. R., & Lee, G. P. (1999). Different contributions
of the human amygdala and ventromedial prefrontal cortex to decision-making.
The Journal of Neuroscience, 19(3), 5473-5481.

LeDoux, J. (2007). The amygdala. Current Biology, 17, 868-874.

Amygdala

Cmcfall — Sun, 27 Apr 2008 21:36:19 GMT

Cmcfall:

[[Category:Brain areas]]

==Overview==

The amygdala represents an anatomical structure of the brain that is involved in a range of behavioral and mental conditions (LeDoux, 2007). Previously, this area had received little scientific recognition, but now it is one of the most extensively studied brain regions. The name “amygdala” is rooted in Greek and refers to the almond-shaped structure located bilaterally within the temporal lobes of the limbic system (LeDoux, 2007). Most individuals assume the amygdala to be comprised of a single mass; however, its composition includes several nuclei, which can be found in species of higher cognitive functioning, including humans and primates. Consistent with this view, it can be argued that the amygdala is not a unitary structure or function, but rather accords several regions that contribute to cognitive functions of other areas in the brain (LeDoux, 2007). In specific, the lateral and basal amygdala are viewed as nuclear extensions of the cortex, while the central and medial nuclei are part of ventral expansions of the striatum and each of these areas can further be divided into subnuclei, which are all relevant to the study of this anatomical region. For example, the dorsal subcomponent of the lateral nucleus is said to be involved in varying aspects of fear memory (LeDoux, 2007).

[[Image:Amygdala-hippocampus.jpg]]

==Connectivity==

The importance of connectivity points to the ability for specific areas of the brain to make connections with other related regions for the purpose of function (LeDoux, 2007). For instance, the lateral amygdala is responsible for receiving stimulatory input from different sensory systems, such as the visual, somatosensory, olfactory, and auditory modalities (LeDoux, 2007). These inputs are then transferred and consummated in the dorsal subnucleus. This subregion then relays information to the ventrolateral and medial areas in order to connect with other areas of the amygdala (LeDoux, 2007).
The region most notable in behavioral and physiological output is the central nucleus, in which connections from the medial subarea and other interconnected nuclei (e.g. basal nucleus) are involved, at least for the expression of emotional responses. As previously mentioned, areas in the striatum also connect with the central nucleus in instrumental behaviors (LeDoux, 2007). More specifically, sensory output from the central amygdala to the brainstem results in the management of emotions, but the interconnectivity between the basal subregion and the striatum are responsible for controlling action-based behaviors, like running from a potential marauder. Finally, the extent to which the connections are successful in relaying communication relies on the role of various neurotransmitter systems, such as dopamine and serotonin, thereby resulting in exhibitory and inhibitory behavioral responses (LeDoux, 2007).

==Behavior==

In the early 20th century, observed damage in the temporal lobe showed profound changes in behaviors such as fear and sex-related responses (LeDoux, 2007). After determining that the amygdala played a role in these impairments, the inability to account for the underlying substructures of this area resulted in a body of research that was widely misunderstood. It was not until after the discovery of the amygdala’s subcomponents, in which researchers were able to study specific behavioral functions associated with this region (LeDoux, 2007).

'''Fear'''

Fear has been documented throughout scientific literature and more specifically, use of Pavlovian conditioning (the seemingly innate ability to learn stimulus-response (SR) affiliations when presented with associative stimuli) has been shown to consistently and effectively measure such behavior (LeDoux, 2007). The habituation of these associations, through prolonged exposure, implies the developmental aspect of plasticity to aid in the maintenance of short-term memory. Moreover, when these SR associations are re-presented to an individual, the enduring plasticity reveals storage of the appropriate information to the individual’s long-term memory (LeDoux, 2007). While fear response continues to be the most salient behavioral function associated with the amygdala, other research has pointed out that this region is also involved in other emotions such as aggression, sexuality, and addictive, ingestive behaviors (e.g. eating and drinking). Additionally, the amygdala’s ability to release hormones, through neurotransmitter modalities, to other regions of the brain also influences other specific types of cognition, such as attention, perception, and explicit memory (LeDoux, 2007). In other words, the amygdala’s emotional processing to external stimuli establishes connections with other functions of the brain. As earlier noted, the amygdala plays a role in several psychiatric conditions, like autism, schizophrenia, borderline personality disorder, and depression. More importantly, the amygdala is not the cause of these disorders, but rather alterations in the representation of this region result in specific behavioral changes in these individuals (LeDoux, 2007).

'''Relevant Studies'''

Bechara, Tranel, Damasio, Adolphs, Rockland, and Damasio (1995) studied the double dissociation between conditioning and declarative knowledge in relation to the amygdala and the hippocampus in three patients. In two conditioning experiments, using a skin conductance response (SCR) measure, the researchers found that the patient with bilateral damage to the amygdala was unable to acquire the conditioned autonomic responses to the presented visual or auditory stimuli; however, declarative knowledge of the stimuli was largely spared (Bechara et al., 1995). Conversely, the patient with hippocampal damage was able to acquire the conditioned autonomic responses, but failed to retain declarative knowledge of the material. Lastly, the third patient had damage to both brain areas, resulting in an inability to acquire both conditioned autonomic responses and declarative facts. Consistent with previous research, this study further suggested the role the amygdala plays in associative cues of affect, while the hippocampus is responsible for learning the critical relationships among these cues (Bechara et al., 1995).
A later study conducted by Bechara, Damasio, Damasio, and Lee (1999) focused on the contributions of the amygdala and the ventromedial prefrontal (VMF) cortex in human decision-making. Using the “gambling task” to measure decision-making and a skin conductance response (SCR) instrument, the researchers were able to effectively study a group of patients with bilateral amygdala damage and another group with VMF bilateral damage (Bechara et al., 1999). In a Pavlovian conditioning experiment, participants were also tested for acquisition of a conditioned SCR to paired visual stimuli and an aversive loud noise (Bechara et al., 1999). Results of the study revealed that the two areas have distinct influences on decision-making. More specifically, patients with amygdala damage were unable to produce SCRs on both the “gambling task” as well as the conditioning experiment. The group of individuals with VMF damage were also unable to generate SCRs on the “gambling task,” but were able to produce a response when presented with a reward or punishment (e.g. play money), while the amygdala-damaged patients still failed to produce such a response when they received similar reinforcements (Bechara et al., 1999).
The differences associated with decision-making in the two groups implies potentially bigger consequences for the patients with bilateral amygdala damage, in that the failure to evoke the appropriate somatic state results in impairment of future decision-making tasks that elicit similar somatic affects (Bechara, 1999). In sum, this study paralleled earlier research about the underlying functions of the orbitofrontal cortex and the basolateral amygdala and their association with goal-directed behavior. While both groups of patients showed impairments on similar decision-making tasks, the individuals with bilateral damage to the amygdala are much more susceptible to both psychologically and physically harmful real-life situations, where a decision may be critical (Bechara, 1999). In other words, their overall failure to adequately respond to external stimuli due to alterations in emotional states (e.g. fear), may therefore cause such individuals to choose a course of action, in which an unfavorable outcome could result in devastating mental and/or physical consequences.

'''Interesting fact'''

The amygdala is responsible for the emotional reactions to music.

==References==

Bechara, A., Tranel, D., Damasio, H., Adolphs, R., Rockland, C., & Damasio, A. R.
(1995). Double dissociation of conditioning and declarative knowledge relative
to the amygdala and hippocampus in humans. Science, 269, 1115-1118.

Bechara, A., Damasio, H., Damasio, A. R., & Lee, G. P. (1999). Different contributions
of the human amygdala and ventromedial prefrontal cortex to decision-making.
The Journal of Neuroscience, 19(3), 5473-5481.

LeDoux, J. (2007). The amygdala. Current Biology, 17, 868-874.

File:Amygdala-hippocampus.jpg

Cmcfall — Sun, 27 Apr 2008 21:35:34 GMT

Cmcfall:

Amygdala

Cmcfall — Sun, 27 Apr 2008 21:34:31 GMT

Cmcfall:

[[Category:Brain areas]]

==Overview==

The amygdala represents an anatomical structure of the brain that is involved in a range of behavioral and mental conditions (LeDoux, 2007). Previously, this area had received little scientific recognition, but now it is one of the most extensively studied brain regions. The name “amygdala” is rooted in Greek and refers to the almond-shaped structure located bilaterally within the temporal lobes of the limbic system (LeDoux, 2007). Most individuals assume the amygdala to be comprised of a single mass; however, its composition includes several nuclei, which can be found in species of higher cognitive functioning, including humans and primates. Consistent with this view, it can be argued that the amygdala is not a unitary structure or function, but rather accords several regions that contribute to cognitive functions of other areas in the brain (LeDoux, 2007). In specific, the lateral and basal amygdala are viewed as nuclear extensions of the cortex, while the central and medial nuclei are part of ventral expansions of the striatum and each of these areas can further be divided into subnuclei, which are all relevant to the study of this anatomical region. For example, the dorsal subcomponent of the lateral nucleus is said to be involved in varying aspects of fear memory (LeDoux, 2007).

==Connectivity==

The importance of connectivity points to the ability for specific areas of the brain to make connections with other related regions for the purpose of function (LeDoux, 2007). For instance, the lateral amygdala is responsible for receiving stimulatory input from different sensory systems, such as the visual, somatosensory, olfactory, and auditory modalities (LeDoux, 2007). These inputs are then transferred and consummated in the dorsal subnucleus. This subregion then relays information to the ventrolateral and medial areas in order to connect with other areas of the amygdala (LeDoux, 2007).
The region most notable in behavioral and physiological output is the central nucleus, in which connections from the medial subarea and other interconnected nuclei (e.g. basal nucleus) are involved, at least for the expression of emotional responses. As previously mentioned, areas in the striatum also connect with the central nucleus in instrumental behaviors (LeDoux, 2007). More specifically, sensory output from the central amygdala to the brainstem results in the management of emotions, but the interconnectivity between the basal subregion and the striatum are responsible for controlling action-based behaviors, like running from a potential marauder. Finally, the extent to which the connections are successful in relaying communication relies on the role of various neurotransmitter systems, such as dopamine and serotonin, thereby resulting in exhibitory and inhibitory behavioral responses (LeDoux, 2007).

==Behavior==

In the early 20th century, observed damage in the temporal lobe showed profound changes in behaviors such as fear and sex-related responses (LeDoux, 2007). After determining that the amygdala played a role in these impairments, the inability to account for the underlying substructures of this area resulted in a body of research that was widely misunderstood. It was not until after the discovery of the amygdala’s subcomponents, in which researchers were able to study specific behavioral functions associated with this region (LeDoux, 2007).

'''Fear'''

Fear has been documented throughout scientific literature and more specifically, use of Pavlovian conditioning (the seemingly innate ability to learn stimulus-response (SR) affiliations when presented with associative stimuli) has been shown to consistently and effectively measure such behavior (LeDoux, 2007). The habituation of these associations, through prolonged exposure, implies the developmental aspect of plasticity to aid in the maintenance of short-term memory. Moreover, when these SR associations are re-presented to an individual, the enduring plasticity reveals storage of the appropriate information to the individual’s long-term memory (LeDoux, 2007). While fear response continues to be the most salient behavioral function associated with the amygdala, other research has pointed out that this region is also involved in other emotions such as aggression, sexuality, and addictive, ingestive behaviors (e.g. eating and drinking). Additionally, the amygdala’s ability to release hormones, through neurotransmitter modalities, to other regions of the brain also influences other specific types of cognition, such as attention, perception, and explicit memory (LeDoux, 2007). In other words, the amygdala’s emotional processing to external stimuli establishes connections with other functions of the brain. As earlier noted, the amygdala plays a role in several psychiatric conditions, like autism, schizophrenia, borderline personality disorder, and depression. More importantly, the amygdala is not the cause of these disorders, but rather alterations in the representation of this region result in specific behavioral changes in these individuals (LeDoux, 2007).

'''Relevant Studies'''

Bechara, Tranel, Damasio, Adolphs, Rockland, and Damasio (1995) studied the double dissociation between conditioning and declarative knowledge in relation to the amygdala and the hippocampus in three patients. In two conditioning experiments, using a skin conductance response (SCR) measure, the researchers found that the patient with bilateral damage to the amygdala was unable to acquire the conditioned autonomic responses to the presented visual or auditory stimuli; however, declarative knowledge of the stimuli was largely spared (Bechara et al., 1995). Conversely, the patient with hippocampal damage was able to acquire the conditioned autonomic responses, but failed to retain declarative knowledge of the material. Lastly, the third patient had damage to both brain areas, resulting in an inability to acquire both conditioned autonomic responses and declarative facts. Consistent with previous research, this study further suggested the role the amygdala plays in associative cues of affect, while the hippocampus is responsible for learning the critical relationships among these cues (Bechara et al., 1995).
A later study conducted by Bechara, Damasio, Damasio, and Lee (1999) focused on the contributions of the amygdala and the ventromedial prefrontal (VMF) cortex in human decision-making. Using the “gambling task” to measure decision-making and a skin conductance response (SCR) instrument, the researchers were able to effectively study a group of patients with bilateral amygdala damage and another group with VMF bilateral damage (Bechara et al., 1999). In a Pavlovian conditioning experiment, participants were also tested for acquisition of a conditioned SCR to paired visual stimuli and an aversive loud noise (Bechara et al., 1999). Results of the study revealed that the two areas have distinct influences on decision-making. More specifically, patients with amygdala damage were unable to produce SCRs on both the “gambling task” as well as the conditioning experiment. The group of individuals with VMF damage were also unable to generate SCRs on the “gambling task,” but were able to produce a response when presented with a reward or punishment (e.g. play money), while the amygdala-damaged patients still failed to produce such a response when they received similar reinforcements (Bechara et al., 1999).
The differences associated with decision-making in the two groups implies potentially bigger consequences for the patients with bilateral amygdala damage, in that the failure to evoke the appropriate somatic state results in impairment of future decision-making tasks that elicit similar somatic affects (Bechara, 1999). In sum, this study paralleled earlier research about the underlying functions of the orbitofrontal cortex and the basolateral amygdala and their association with goal-directed behavior. While both groups of patients showed impairments on similar decision-making tasks, the individuals with bilateral damage to the amygdala are much more susceptible to both psychologically and physically harmful real-life situations, where a decision may be critical (Bechara, 1999). In other words, their overall failure to adequately respond to external stimuli due to alterations in emotional states (e.g. fear), may therefore cause such individuals to choose a course of action, in which an unfavorable outcome could result in devastating mental and/or physical consequences.

'''Interesting fact'''

The amygdala is responsible for the emotional reactions to music.

==References==

Bechara, A., Tranel, D., Damasio, H., Adolphs, R., Rockland, C., & Damasio, A. R.
(1995). Double dissociation of conditioning and declarative knowledge relative
to the amygdala and hippocampus in humans. Science, 269, 1115-1118.

Bechara, A., Damasio, H., Damasio, A. R., & Lee, G. P. (1999). Different contributions
of the human amygdala and ventromedial prefrontal cortex to decision-making.
The Journal of Neuroscience, 19(3), 5473-5481.

LeDoux, J. (2007). The amygdala. Current Biology, 17, 868-874.

Amygdala

Cmcfall — Sun, 27 Apr 2008 21:33:49 GMT

Cmcfall:

[[Category:Brain areas]]

==Overview==

The amygdala represents an anatomical structure of the brain that is involved in a range of behavioral and mental conditions (LeDoux, 2007). Previously, this area had received little scientific recognition, but now it is one of the most extensively studied brain regions. The name “amygdala” is rooted in Greek and refers to the almond-shaped structure located bilaterally within the temporal lobes of the limbic system (LeDoux, 2007). Most individuals assume the amygdala to be comprised of a single mass; however, its composition includes several nuclei, which can be found in species of higher cognitive functioning, including humans and primates. Consistent with this view, it can be argued that the amygdala is not a unitary structure or function, but rather accords several regions that contribute to cognitive functions of other areas in the brain (LeDoux, 2007). In specific, the lateral and basal amygdala are viewed as nuclear extensions of the cortex, while the central and medial nuclei are part of ventral expansions of the striatum and each of these areas can further be divided into subnuclei, which are all relevant to the study of this anatomical region. For example, the dorsal subcomponent of the lateral nucleus is said to be involved in varying aspects of fear memory (LeDoux, 2007).

==Connectivity==

The importance of connectivity points to the ability for specific areas of the brain to make connections with other related regions for the purpose of function (LeDoux, 2007). For instance, the lateral amygdala is responsible for receiving stimulatory input from different sensory systems, such as the visual, somatosensory, olfactory, and auditory modalities (LeDoux, 2007). These inputs are then transferred and consummated in the dorsal subnucleus. This subregion then relays information to the ventrolateral and medial areas in order to connect with other areas of the amygdala (LeDoux, 2007).
The region most notable in behavioral and physiological output is the central nucleus, in which connections from the medial subarea and other interconnected nuclei (e.g. basal nucleus) are involved, at least for the expression of emotional responses. As previously mentioned, areas in the striatum also connect with the central nucleus in instrumental behaviors (LeDoux, 2007). More specifically, sensory output from the central amygdala to the brainstem results in the management of emotions, but the interconnectivity between the basal subregion and the striatum are responsible for controlling action-based behaviors, like running from a potential marauder. Finally, the extent to which the connections are successful in relaying communication relies on the role of various neurotransmitter systems, such as dopamine and serotonin, thereby resulting in exhibitory and inhibitory behavioral responses (LeDoux, 2007).

==Behavior==

In the early 20th century, observed damage in the temporal lobe showed profound changes in behaviors such as fear and sex-related responses (LeDoux, 2007). After determining that the amygdala played a role in these impairments, the inability to account for the underlying substructures of this area resulted in a body of research that was widely misunderstood. It was not until after the discovery of the amygdala’s subcomponents, in which researchers were able to study specific behavioral functions associated with this region (LeDoux, 2007).

'''Fear'''

Fear has been documented throughout scientific literature and more specifically, use of Pavlovian conditioning (the seemingly innate ability to learn stimulus-response (SR) affiliations when presented with associative stimuli) has been shown to consistently and effectively measure such behavior (LeDoux, 2007). The habituation of these associations, through prolonged exposure, implies the developmental aspect of plasticity to aid in the maintenance of short-term memory. Moreover, when these SR associations are re-presented to an individual, the enduring plasticity reveals storage of the appropriate information to the individual’s long-term memory (LeDoux, 2007). While fear response continues to be the most salient behavioral function associated with the amygdala, other research has pointed out that this region is also involved in other emotions such as aggression, sexuality, and addictive, ingestive behaviors (e.g. eating and drinking). Additionally, the amygdala’s ability to release hormones, through neurotransmitter modalities, to other regions of the brain also influences other specific types of cognition, such as attention, perception, and explicit memory (LeDoux, 2007). In other words, the amygdala’s emotional processing to external stimuli establishes connections with other functions of the brain. As earlier noted, the amygdala plays a role in several psychiatric conditions, like autism, schizophrenia, borderline personality disorder, and depression. More importantly, the amygdala is not the cause of these disorders, but rather alterations in the representation of this region result in specific behavioral changes in these individuals (LeDoux, 2007).

'''Relevant Studies'''

Bechara, Tranel, Damasio, Adolphs, Rockland, and Damasio (1995) studied the double dissociation between conditioning and declarative knowledge in relation to the amygdala and the hippocampus in three patients. In two conditioning experiments, using a skin conductance response (SCR) measure, the researchers found that the patient with bilateral damage to the amygdala was unable to acquire the conditioned autonomic responses to the presented visual or auditory stimuli; however, declarative knowledge of the stimuli was largely spared (Bechara et al., 1995). Conversely, the patient with hippocampal damage was able to acquire the conditioned autonomic responses, but failed to retain declarative knowledge of the material. Lastly, the third patient had damage to both brain areas, resulting in an inability to acquire both conditioned autonomic responses and declarative facts. Consistent with previous research, this study further suggested the role the amygdala plays in associative cues of affect, while the hippocampus is responsible for learning the critical relationships among these cues (Bechara et al., 1995).
A later study conducted by Bechara, Damasio, Damasio, and Lee (1999) focused on the contributions of the amygdala and the ventromedial prefrontal (VMF) cortex in human decision-making. Using the “gambling task” to measure decision-making and a skin conductance response (SCR) instrument, the researchers were able to effectively study a group of patients with bilateral amygdala damage and another group with VMF bilateral damage (Bechara et al., 1999). In a Pavlovian conditioning experiment, participants were also tested for acquisition of a conditioned SCR to paired visual stimuli and an aversive loud noise (Bechara et al., 1999). Results of the study revealed that the two areas have distinct influences on decision-making. More specifically, patients with amygdala damage were unable to produce SCRs on both the “gambling task” as well as the conditioning experiment. The group of individuals with VMF damage were also unable to generate SCRs on the “gambling task,” but were able to produce a response when presented with a reward or punishment (e.g. play money), while the amygdala-damaged patients still failed to produce such a response when they received similar reinforcements (Bechara et al., 1999).
The differences associated with decision-making in the two groups implies potentially bigger consequences for the patients with bilateral amygdala damage, in that the failure to evoke the appropriate somatic state results in impairment of future decision-making tasks that elicit similar somatic affects (Bechara, 1999). In sum, this study paralleled earlier research about the underlying functions of the orbitofrontal cortex and the basolateral amygdala and their association with goal-directed behavior. While both groups of patients showed impairments on similar decision-making tasks, the individuals with bilateral damage to the amygdala are much more susceptible to both psychologically and physically harmful real-life situations, where a decision may be critical (Bechara, 1999). In other words, their overall failure to adequately respond to external stimuli due to alterations in emotional states (e.g. fear), may therefore cause such individuals to choose a course of action, in which an unfavorable outcome could result in devastating mental and/or physical consequences.

Interesting fact:

The amygdala is responsible for the emotional reactions to music.

==References==

Bechara, A., Tranel, D., Damasio, H., Adolphs, R., Rockland, C., & Damasio, A. R.
(1995). Double dissociation of conditioning and declarative knowledge relative
to the amygdala and hippocampus in humans. Science, 269, 1115-1118.

Bechara, A., Damasio, H., Damasio, A. R., & Lee, G. P. (1999). Different contributions
of the human amygdala and ventromedial prefrontal cortex to decision-making.
The Journal of Neuroscience, 19(3), 5473-5481.

LeDoux, J. (2007). The amygdala. Current Biology, 17, 868-874.

Amygdala

Cmcfall — Sun, 27 Apr 2008 21:28:24 GMT

Cmcfall:

[[Category:Brain areas]]

Overview

The amygdala represents an anatomical structure of the brain that is involved in a range of behavioral and mental conditions (LeDoux, 2007). Previously, this area had received little scientific recognition, but now it is one of the most extensively studied brain regions. The name “amygdala” is rooted in Greek and refers to the almond-shaped structure located bilaterally within the temporal lobes of the limbic system (LeDoux, 2007). Most individuals assume the amygdala to be comprised of a single mass; however, its composition includes several nuclei, which can be found in species of higher cognitive functioning, including humans and primates. Consistent with this view, it can be argued that the amygdala is not a unitary structure or function, but rather accords several regions that contribute to cognitive functions of other areas in the brain (LeDoux, 2007). In specific, the lateral and basal amygdala are viewed as nuclear extensions of the cortex, while the central and medial nuclei are part of ventral expansions of the striatum and each of these areas can further be divided into subnuclei, which are all relevant to the study of this anatomical region. For example, the dorsal subcomponent of the lateral nucleus is said to be involved in varying aspects of fear memory (LeDoux, 2007).

Connectivity

The importance of connectivity points to the ability for specific areas of the brain to make connections with other related regions for the purpose of function (LeDoux, 2007). For instance, the lateral amygdala is responsible for receiving stimulatory input from different sensory systems, such as the visual, somatosensory, olfactory, and auditory modalities (LeDoux, 2007). These inputs are then transferred and consummated in the dorsal subnucleus. This subregion then relays information to the ventrolateral and medial areas in order to connect with other areas of the amygdala (LeDoux, 2007).
The region most notable in behavioral and physiological output is the central nucleus, in which connections from the medial subarea and other interconnected nuclei (e.g. basal nucleus) are involved, at least for the expression of emotional responses. As previously mentioned, areas in the striatum also connect with the central nucleus in instrumental behaviors (LeDoux, 2007). More specifically, sensory output from the central amygdala to the brainstem results in the management of emotions, but the interconnectivity between the basal subregion and the striatum are responsible for controlling action-based behaviors, like running from a potential marauder. Finally, the extent to which the connections are successful in relaying communication relies on the role of various neurotransmitter systems, such as dopamine and serotonin, thereby resulting in exhibitory and inhibitory behavioral responses (LeDoux, 2007).

Behavior

In the early 20th century, observed damage in the temporal lobe showed profound changes in behaviors such as fear and sex-related responses (LeDoux, 2007). After determining that the amygdala played a role in these impairments, the inability to account for the underlying substructures of this area resulted in a body of research that was widely misunderstood. It was not until after the discovery of the amygdala’s subcomponents, in which researchers were able to study specific behavioral functions associated with this region (LeDoux, 2007).

Fear

Fear has been documented throughout scientific literature and more specifically, use of Pavlovian conditioning (the seemingly innate ability to learn stimulus-response (SR) affiliations when presented with associative stimuli) has been shown to consistently and effectively measure such behavior (LeDoux, 2007). The habituation of these associations, through prolonged exposure, implies the developmental aspect of plasticity to aid in the maintenance of short-term memory. Moreover, when these SR associations are re-presented to an individual, the enduring plasticity reveals storage of the appropriate information to the individual’s long-term memory (LeDoux, 2007). While fear response continues to be the most salient behavioral function associated with the amygdala, other research has pointed out that this region is also involved in other emotions such as aggression, sexuality, and addictive, ingestive behaviors (e.g. eating and drinking). Additionally, the amygdala’s ability to release hormones, through neurotransmitter modalities, to other regions of the brain also influences other specific types of cognition, such as attention, perception, and explicit memory (LeDoux, 2007). In other words, the amygdala’s emotional processing to external stimuli establishes connections with other functions of the brain. As earlier noted, the amygdala plays a role in several psychiatric conditions, like autism, schizophrenia, borderline personality disorder, and depression. More importantly, the amygdala is not the cause of these disorders, but rather alterations in the representation of this region result in specific behavioral changes in these individuals (LeDoux, 2007).

Relevant Studies

Bechara, Tranel, Damasio, Adolphs, Rockland, and Damasio (1995) studied the double dissociation between conditioning and declarative knowledge in relation to the amygdala and the hippocampus in three patients. In two conditioning experiments, using a skin conductance response (SCR) measure, the researchers found that the patient with bilateral damage to the amygdala was unable to acquire the conditioned autonomic responses to the presented visual or auditory stimuli; however, declarative knowledge of the stimuli was largely spared (Bechara et al., 1995). Conversely, the patient with hippocampal damage was able to acquire the conditioned autonomic responses, but failed to retain declarative knowledge of the material. Lastly, the third patient had damage to both brain areas, resulting in an inability to acquire both conditioned autonomic responses and declarative facts. Consistent with previous research, this study further suggested the role the amygdala plays in associative cues of affect, while the hippocampus is responsible for learning the critical relationships among these cues (Bechara et al., 1995).
A later study conducted by Bechara, Damasio, Damasio, and Lee (1999) focused on the contributions of the amygdala and the ventromedial prefrontal (VMF) cortex in human decision-making. Using the “gambling task” to measure decision-making and a skin conductance response (SCR) instrument, the researchers were able to effectively study a group of patients with bilateral amygdala damage and another group with VMF bilateral damage (Bechara et al., 1999). In a Pavlovian conditioning experiment, participants were also tested for acquisition of a conditioned SCR to paired visual stimuli and an aversive loud noise (Bechara et al., 1999). Results of the study revealed that the two areas have distinct influences on decision-making. More specifically, patients with amygdala damage were unable to produce SCRs on both the “gambling task” as well as the conditioning experiment. The group of individuals with VMF damage were also unable to generate SCRs on the “gambling task,” but were able to produce a response when presented with a reward or punishment (e.g. play money), while the amygdala-damaged patients still failed to produce such a response when they received similar reinforcements (Bechara et al., 1999).
The differences associated with decision-making in the two groups implies potentially bigger consequences for the patients with bilateral amygdala damage, in that the failure to evoke the appropriate somatic state results in impairment of future decision-making tasks that elicit similar somatic affects (Bechara, 1999). In sum, this study paralleled earlier research about the underlying functions of the orbitofrontal cortex and the basolateral amygdala and their association with goal-directed behavior. While both groups of patients showed impairments on similar decision-making tasks, the individuals with bilateral damage to the amygdala are much more susceptible to both psychologically and physically harmful real-life situations, where a decision may be critical (Bechara, 1999). In other words, their overall failure to adequately respond to external stimuli due to alterations in emotional states (e.g. fear), may therefore cause such individuals to choose a course of action, in which an unfavorable outcome could result in devastating mental and/or physical consequences.

References

Bechara, A., Tranel, D., Damasio, H., Adolphs, R., Rockland, C., & Damasio, A. R.
(1995). Double dissociation of conditioning and declarative knowledge relative
to the amygdala and hippocampus in humans. Science, 269, 1115-1118.

Bechara, A., Damasio, H., Damasio, A. R., & Lee, G. P. (1999). Different contributions
of the human amygdala and ventromedial prefrontal cortex to decision-making.
The Journal of Neuroscience, 19(3), 5473-5481.

LeDoux, J. (2007). The amygdala. Current Biology, 17, 868-874.

Interesting fact:

The amygdala is responsible for the emotional reactions to music.

Hippocampus

Cmcfall — Thu, 24 Apr 2008 00:39:40 GMT

Cmcfall:

[[Category:Brain areas]]

Interesting fact:

The hippocampus is responsible for remembering music(memory),musical experiences and contexts.

http://youtube.com/watch?v=YYJ4VTqhoy8&feature=related

Rey-Osterreith complex figure

Cmcfall — Thu, 24 Apr 2008 00:30:43 GMT

Cmcfall:

[[Category:Neuropsychological methods]]

[[Image:Reyosterrieth.gif]]

File:Reyosterrieth.gif

Cmcfall — Thu, 24 Apr 2008 00:29:19 GMT

Cmcfall:

File:Stroop.jpg

Cmcfall — Thu, 24 Apr 2008 00:27:06 GMT

Cmcfall: Stroop Task

Stroop Task

Schizophrenia

Cmcfall — Thu, 24 Apr 2008 00:25:48 GMT

Cmcfall:

[[Category:Neuropsychological syndromes]]

[[Image:Schizophrenia.jpg]]

File:Schizophrenia.jpg

Cmcfall — Thu, 24 Apr 2008 00:25:10 GMT

Cmcfall:

Broca's aphasia

Cmcfall — Thu, 24 Apr 2008 00:22:04 GMT

Cmcfall:

[[Category:Neuropsychological syndromes]]
Named after Paul Broca in 1861, Broca's aphasia is a motor speech disorder that results in one's inability to properly pronounce and/or remember words correctly. Such non fluency in the pronunciation of words can result in incoherent responses like "Speech" pronounced as "peech" or "talk" will sound like "palk". This is because letters like p, b, and m are formed at the front of the mouth while s and t are harder to pronounce with motor skills disorders. Also, patients suffering from Broca's Aphasia tend to use verbs in a more simple form such as "me go" instead of "I am going" (86, Ogden). Paul Broca's patient Leborgne, also known as "Tan", constantly mumbled this word, hence the name. "Tan" suffered a lesion on the third frontal gyrus. The frontal gyrus, which is known as the Broca's area is in high correlation to the motor-speech memories. Adjacent to the Broca's area, the precentral gyrus features the motor neurons for the tongue and lips. Issues with either/both of these areas easily result with incoherently pronounced words.

To learn more about Paul Broca go to the Paul Broca Wiki page.

OTHER AREAS OF DIFFICULTY:

One's right hand can become paralyzed as the lesion of the brain that relates to the frontal gyrus can invade the motor strip of the hand. This often happens with Broca's patients and such physical disorders leads these Broca's patients to attempt to write with their non paralyzed left hands. Unfortunately, switching hands results in non fluent writing including misspelled words, inaccurate grammar, and words that are left out completely. Ogden states that copying can be the best option for this situation.

Many Broca's patients suffer from oral apraxia, which demonstrates a high correlation between the two. Oral apraxia results in patients having trouble performing learned motor skills on command. Patients who have a severe diagnosis of oral apraxia tend to be unable to imitate the instructor with such tasks as whistling or sticking one's tongue out.

As stated before, the paralysis of the right arm generally goes with the Broca's aphasia. If the patient can improve his/her speech, the paralyzed arm usually can become usable again. However, if the speech does not improve, then generally the paralyzed arm will remain inept to any form of use.

[[Image:Brocasaphasia1.jpg]]