Psy3241 - User contributions [en]

Rey-Osterreith complex figure

2008-04-25T00:53:08Z

Aterr:

[[Category:Neuropsychological methods]]

The Rey-Osterreith complex figure (ROCF) was created by the Swiss psychologist Andre Rey in 1941. Rey created this figure to assess perceptual organization and visual memory in subjects with brain injury. Standardized instructions for the complex figure were published by Osterreith in 1944. Recently, this neuropsychological test has been widely used in subjects of all ages as a tool for measuring the decision-making function that is arbitrated by the prefrontal lobe. The ROCF is comprised of three test conditions: copy, immediate recall, and delayed recall. In the copy condition, the subjects are given the ROCF and asked to draw what they see. Then, in the immediate recall condition, the subjects are shown the complex figure again and then asked to draw what they remember immediately after the figure is removed. Finally, in the delayed recall condition, the subjects are shown the complex figure, and after a delay of thirty minutes are asked to draw the same figure again. The subjects are allotted ten minutes for each section of the ROCF. A similar test, the Modified Taylor Complex Figure, was developed as an alternative to the ROCF but has been shown in many recent studies to be easier to learn and remember as well as producing analogous total scores, completion times, and validity coefficients.

"http://www.nature.com/nprot/journal/v1/n2/images/nprot.2006.115-F1.gif"

Rey-Osterreith complex figure

2008-04-25T00:52:05Z

Aterr:

[[Category:Neuropsychological methods]]

The Rey-Osterreith complex figure (ROCF) was created by the Swiss psychologist Andre Rey in 1941. Rey created this figure to assess perceptual organization and visual memory in subjects with brain injury. Standardized instructions for the complex figure were published by Osterreith in 1944. Recently, this neuropsychological test has been widely used in subjects of all ages as a tool for measuring the decision-making function that is arbitrated by the prefrontal lobe. The ROCF is comprised of three test conditions: copy, immediate recall, and delayed recall. In the copy condition, the subjects are given the ROCF and asked to draw what they see. Then, in the immediate recall condition, the subjects are shown the complex figure again and then asked to draw what they remember immediately after the figure is removed. Finally, in the delayed recall condition, the subjects are shown the complex figure, and after a delay of thirty minutes are asked to draw the same figure again. The subjects are allotted ten minutes for each section of the ROCF. A similar test, the Modified Taylor Complex Figure, was developed as an alternative to the ROCF but has been shown in many recent studies to be easier to learn and remember as well as producing analogous total scores, completion times, and validity coefficients.
[[Image:Example.jpg]]

<img src="http://www.nature.com/nprot/journal/v1/n2/images/nprot.2006.115-F1.gif">

Basal ganglia

2008-04-25T00:40:37Z

Aterr: /* What It Does. */

[[Category:Brain areas]]

== What It Is. ==

The basal ganglia are a collection of nuclei found on both sides of the thalamus, outside and above the limbic system, below the cingulate gyrus, and within the temporal lobes. The basal ganglia are associated with movement, cognition, emotions, and learning. There are two sets of basal ganglia in the brain, one in the right hemisphere and one in the left. The basal ganglia are comprised of a series of circuits that project to specific nuclei within the basal ganglia. The largest group of these nuclei is called the corpus striatum. The corpus striatum is made up of the caudate nucleus, the putamen, the globus pallidus, and the nucleus accumbens.
[http://www.youtube.com/watch?v=EluAk9NWOJI Basal ganglia video]

== Components ==

The caudate nucleus sends messages to the frontal lobe and is responsible for informing one that something is not right and that one should formulate a proper action to fix the problem. Obsessive compulsive disorder is a result of an overactive caudate, whereas ADD, depression, and lethargy are all results of an underactive caudate. The putamen is involved in coordinating automatic behaviors such as riding a bike. The globus pallidus receives inputs from the caudate and putamen and provides outputs to the substantia nigra which acts to facilitate the movement. The globus pallidus consists of two parts, globus pallidus externa and globus pallidus interna. Globus pallidus interna specifically deals with inhibiting all movements one will not do and defining the amplitude of the movement. The nucleus accumbens receives input signals in the form of dopamine from the prefrontal cortex and sends signals back through the globus pallidus.

== What It Does. ==

The basal ganglia are responsible for all ballistic movements. Ballistic movements are open loop movements with no necessarily defined endpoint. These movements also help to modify voluntary movements. The basal ganglia select the movement by considering all possibilities and suppressing all but one, and scale the movement by regulating its amplitude. The motor functions of a human greatly rely upon the corpus striatum because it is the main input zone for other brain areas to connect to the basal ganglia. The circuit begins in the motor cortex which sends input to the basal ganglia via the striatum, then to the motor regions of the thalamus, and back to the motor cortex. What the motor cortex sends to the spinal cord depends on what occurs during the loop. In short, the basal ganglia inhibit the thalamus which in turn excites the cortex, causing movement. Inside the basal ganglia are two circuits. The first, the Direct Pathway, facilitates movement by disinhibition or inhibiting the inhibition. The Indirect Pathway discourages movement by inhibiting the globus pallidus externa, which inhibits the globus pallidus interna, which finally inhibits the thalamus which would have sent neurotransmitters to the motor cortex (inhibiting the disinhibition).

The substantia nigra is a very important part of the basal ganglia circuit because it releases dopamine which is a key toward facilitating the actual movement. It facilitates movement by releasing dopamine that excites the direct pathway and inhibits the indirect pathway. If the substantia nigra is damaged, one loses that ability to excite the direct pathway and inhibit the indirect pathway. In other words, one would lose the ability to amplify any movement one would like to make and inhibit any movement one would not like to make. Thus, both pathways are virtually dependent upon the substantia nigra.

== Results of Damage ==

Lesions in specific nuclei of the basal ganglia produce specific deficits. The most famous of which is Parkinson’s Disease which is the slow and pervasive loss of dopamine neurons in the substantia nigra. The symptoms of this disease are tremor, rigidity, and bradykinesia. Huntington’s disease is another example. This disease results from the degeneration of the caudate and putamen and produces continuous movements of the face and limbs.

Basal ganglia

2008-04-25T00:38:44Z

Aterr:

[[Category:Brain areas]]

== What It Is. ==

The basal ganglia are a collection of nuclei found on both sides of the thalamus, outside and above the limbic system, below the cingulate gyrus, and within the temporal lobes. The basal ganglia are associated with movement, cognition, emotions, and learning. There are two sets of basal ganglia in the brain, one in the right hemisphere and one in the left. The basal ganglia are comprised of a series of circuits that project to specific nuclei within the basal ganglia. The largest group of these nuclei is called the corpus striatum. The corpus striatum is made up of the caudate nucleus, the putamen, the globus pallidus, and the nucleus accumbens.
[http://www.youtube.com/watch?v=EluAk9NWOJI Basal ganglia video]

== Components ==

The caudate nucleus sends messages to the frontal lobe and is responsible for informing one that something is not right and that one should formulate a proper action to fix the problem. Obsessive compulsive disorder is a result of an overactive caudate, whereas ADD, depression, and lethargy are all results of an underactive caudate. The putamen is involved in coordinating automatic behaviors such as riding a bike. The globus pallidus receives inputs from the caudate and putamen and provides outputs to the substantia nigra which acts to facilitate the movement. The globus pallidus consists of two parts, globus pallidus externa and globus pallidus interna. Globus pallidus interna specifically deals with inhibiting all movements one will not do and defining the amplitude of the movement. The nucleus accumbens receives input signals in the form of dopamine from the prefrontal cortex and sends signals back through the globus pallidus.

== What It Does. ==

The basal ganglia are responsible for all ballistic movements. Ballistic movements are open loop movements with no necessarily defined endpoint. These movements also help to modify voluntary movements. The basal ganglia select the movement by considering all possibilities and suppressing all but one, and scale the movement by regulating its amplitude. The motor functions of a human greatly rely upon the corpus striatum because it is the main input zone for other brain areas to connect to the basal ganglia. The circuit begins in the motor cortex which sends input to the basal ganglia via the striatum, then to the motor regions of the thalamus, and back to the motor cortex. What the motor cortex sends to the spinal cord depends on what occurs during the loop. In short, the basal ganglia inhibit the thalamus which in turn excites the cortex, causing movement. Inside the basal ganglia are two circuits. The first, the Direct Pathway, facilitates movement by disinhibition or inhibiting the inhibition. The Indirect Pathway discourages movement by inhibiting the globus pallidus externa, which inhibits the globus pallidus interna, which finally inhibits the thalamus which would have sent neurotransmitters to the motor cortex (inhibiting the disinhibition).

The substantia nigra is a very important part of the basal ganglia circuit because it releases dopamine which is a key toward facilitating the actual movement. It facilitates movement by releasing dopamine that excites the direct pathway and inhibits the indirect pathway. If the substantia nigra is damaged, one loses that ability to excite the direct pathway and inhibit the indirect pathway. In other words, one would lose the ability to amplify any movement one would like to make and inhibit any movement one would not like to make. Thus, both pathways are virtually dependent upon the substantia nigra.

==
Results of Damage ==

Lesions in specific nuclei of the basal ganglia produce specific deficits. The most famous of which is Parkinson’s Disease which is the slow and pervasive loss of dopamine neurons in the substantia nigra. The symptoms of this disease are tremor, rigidity, and bradykinesia. Huntington’s disease is another example. This disease results from the degeneration of the caudate and putamen and produces continuous movements of the face and limbs.

Blindsight

2008-04-25T00:35:37Z

Aterr:

[[Category:Neuropsychological syndromes]]

== What it is. ==

Blindsight is an extraordinary neuropsychological phenomenon that occurs after certain kinds of brain lesions, primarily in area V1, causing blindness. It is the ability to respond accurately (better than chance) to visual inputs given, without having the feeling or ability to see them. There are two types of Blindsight. The first type involves people that have no awareness of any objects projected into their blind region, but are able to correctly identify where the object is when pressed to do so. The second type of Blindsight involves people who have awareness of movement in their blind visual field, and are able to accurately ‘guess’ where the object is located.

== How it happens ==

The primary visual cortex is used for conscious vision. Damage to area V1, where the primary visual cortex is located, causes blindness in the opposite visual field of the hemisphere in which the damage was done. For Blindsight to be understood, vision must be understood. Visual processing occurs when ganglion cells of the retina send axons through the optic nerve to the lateral geniculate nucleus. The lateral geniculate nucleus is located in the thalamus and is a primary processor of visual information. It receives the visual information and then projects it to the primary visual cortex, or V1. Information from V1 is then sent to the secondary visual cortex and onto the occipital areas of the ventral and dorsal streams. The dorsal stream projects to the parietal lobe and the ventral stream sends information to the temporal lobe. Damage to the dorsal stream(area’s V3 and V5) causes cerebral akinetopsia (V5) and Balint’s syndrome. Damage to the ventral stream (area’s V4 and V8) causes cerebral achromotopsia (V4) and visual agnosia (V8). Thus it is clear that when there is damage to V1, the visual information processing stream is interrupted and visual deficits result. It is hypothesized that Blindsight and normal vision are controlled by other sections of the brain as a backup to the primary visual cortex. The superior colliculus, for instance, has been proven to take over some of the functions of the primary visual cortex. The superior colliculus supplies blindsighted individuals with the intrinsic feeling of where the object is in their blind visual field. It is used as a reflex for orienting eye and head movements towards something that is seen or heard. The only brain region though that allows for complete sight, local orientation, spatial frequency, and color properties within small receptive fields, is the primary visual cortex.

== Blindtouch ==

[http://espra.risc.cnrs.fr/PAILLARD%20165-localization-without-content%201983.pdf Localization without Content]

Nikolic et al. (2007)

2008-04-24T23:35:25Z

Aterr:

[[Category:Synesthesia Symposium]]

Color Opponency in Synaesthetic Experiences
by Danko Nikolic, Philipp Lichti, and Wolf Singer

What is Synaesthesia?
Synaesthesia is a harmless perceptual condition in which there is a blending of the senses. Generally letters and numbers are seen as different colors or where music initiates the perception of color. A synaesthetic individual could be said to have the ability to see sound. Some synaesthetes are categorized as associators which is the perception of a color on an internal screen or in the mind, while others are considered projectors where color is seen on objects in space such as colored letters on a page.

The Stroop Test
A Stroop test which was developed in 1935 by J. R. Stroop, an individual is instructed to name the ink color of a word that refers to a color. The reaction times to identify the ink color for the individual is measured and analyzed. Reaction times are generally longer if the color of the ink and the meaning of the word do not match (incongruent condition), for example if yellow is written in red ink. This test can be applied to study synaesthetic individuals by adjusting the meaning of the words to match the perceptual experience a person has to that word. In summary, a synaesthetic person would look at a word that evokes a red perception that would be colored in red ink and would be able to react faster than a non-synaesthetic individual.

Color Opponency in Synaesthetic Experiences
In the current study researchers are taking advantage of the color opponent receptive fields of the brain. The color opponent receptive fields are cells that are excited by red and inhibited by green and cells that are excited by yellow and inhibited by blue. This fact allows researchers to study which receptive fields are active during real and synaesthetic perceptions.

Experiment 1
Subjects
6 synaesthetic individuals participated in the study, four were women and two were men and five of these people had other forms of Synaesthesia. 12 nonsynaesthetes participated in the study as the control group who matched the synaesthetes in gender and age.

Procedure
The subjects were tested on color associations. There were three conditions: the congruent condition in which the color of each grapheme was the same as the synaesthetic color; the incongruent opponent condition in which the color of each grapheme was opposite to the synaesthetic color; the incongruent independent condition in which the color of each grapheme and the synaesthetic color were represented by different opponent-color channels; and the baseline condition in which the experimenters used a grapheme that did not have a synaesthetic color association. The experiment took place in a dimly lit room with a computer running the visual stimulation tool. The subjects were given 200 trials in which they were told to accurately name the real color of each grapheme as fast and as they could. The entire experiment took approximately 25 minutes.

What they found!
The subjects response accuracy was very high (98%) but a Tukey HSD test for a post hoc comparison indicated that subjects named the correct color faster in the congruent condition than in the incongruent condition. The experimenters found significant results between the incongruent independent condition (which was named faster) and the incongruent opponent condition. They found that opponent incongruent colors produced more interference than the independent incongruent colors. They also found that the congruent synaesthetic colors helped the subjects to name the real colors of the graphemes.

Experiment 2
The experimenters examined semantic associations between shape and color using the Stroop task. The stimuli that they used were commonly known everyday associations between shape and color. The experimenters hypothesized that semantic associations do not involve the opponent-color system. They used four of the synaesthetes and 8 of the control subjects from experiment 1. They also used the same methods as for the synaesthetic Stroop test except that only three objects were used and each only appeared in three stimulation conditions. The subjects were presented each stimulus 25 times, given a total of 225 trials overall.

What they found!
Once again, the response accuracy was very high, indicating that color opponency does in fact affect the semantic associations between shape and color differently than synaesthetic associations.

Overall, the experimenters concluded that opponent synaesthetic and real colors interfere the most with the naming and perception of a real color. Conversely, when synaesthetic and real colors are identical, the color-naming process is assisted and the response times are decreased. These findings show that the color experiences stimulated by this experiment involve color-opponent channels and thus neurons in the V1 to V4/V8 areas. The results of experiments 1 and 2 suggest that the semantic associations between graphemes and colors explain the interference between nonopponent colors.

Basal ganglia

2008-04-06T00:13:56Z

Aterr:

[[Category:Brain areas]]

The basal ganglia are a collection of nuclei found on both sides of the thalamus, outside and above the limbic system, below the cingulate gyrus, and within the temporal lobes. The basal ganglia are associated with movement, cognition, emotions, and learning. There are two sets of basal ganglia in the brain, one in the right hemisphere and one in the left. The basal ganglia are comprised of a series of circuits that project to specific nuclei within the basal ganglia. The largest group of these nuclei is called the corpus striatum. The corpus striatum is made up of the caudate nucleus, the putamen, the globus pallidus, and the nucleus accumbens.

The caudate nucleus sends messages to the frontal lobe and is responsible for informing one that something is not right and that one should formulate a proper action to fix the problem. Obsessive compulsive disorder is a result of an overactive caudate, whereas ADD, depression, and lethargy are all results of an underactive caudate. The putamen is involved in coordinating automatic behaviors such as riding a bike. The globus pallidus receives inputs from the caudate and putamen and provides outputs to the substantia nigra which acts to facilitate the movement. The globus pallidus consists of two parts, globus pallidus externa and globus pallidus interna. Globus pallidus interna specifically deals with inhibiting all movements one will not do and defining the amplitude of the movement. The nucleus accumbens receives input signals in the form of dopamine from the prefrontal cortex and sends signals back through the globus pallidus.

The basal ganglia are responsible for all ballistic movements. Ballistic movements are open loop movements with no necessarily defined endpoint. These movements also help to modify voluntary movements. The basal ganglia select the movement by considering all possibilities and suppressing all but one, and scale the movement by regulating its amplitude. The motor functions of a human greatly rely upon the corpus striatum because it is the main input zone for other brain areas to connect to the basal ganglia. The circuit begins in the motor cortex which sends input to the basal ganglia via the striatum, then to the motor regions of the thalamus, and back to the motor cortex. What the motor cortex sends to the spinal cord depends on what occurs during the loop. In short, the basal ganglia inhibit the thalamus which in turn excites the cortex, causing movement. Inside the basal ganglia are two circuits. The first, the Direct Pathway, facilitates movement by disinhibition or inhibiting the inhibition. The Indirect Pathway discourages movement by inhibiting the globus pallidus externa, which inhibits the globus pallidus interna, which finally inhibits the thalamus which would have sent neurotransmitters to the motor cortex (inhibiting the disinhibition).

The substantia nigra is a very important part of the basal ganglia circuit because it releases dopamine which is a key toward facilitating the actual movement. It facilitates movement by releasing dopamine that excites the direct pathway and inhibits the indirect pathway. If the substantia nigra is damaged, one loses that ability to excite the direct pathway and inhibit the indirect pathway. In other words, one would lose the ability to amplify any movement one would like to make and inhibit any movement one would not like to make. Thus, both pathways are virtually dependent upon the substantia nigra.

Lesions in specific nuclei of the basal ganglia produce specific deficits. The most famous of which is Parkinson’s Disease which is the slow and pervasive loss of dopamine neurons in the substantia nigra. The symptoms of this disease are tremor, rigidity, and bradykinesia. Huntington’s disease is another example. This disease results from the degeneration of the caudate and putamen and produces continuous movements of the face and limbs.

Basal ganglia

2008-04-06T00:12:43Z

Aterr:

[[Category:Brain areas]]

The basal ganglia are a collection of nuclei found on both sides of the thalamus, outside and above the limbic system, below the cingulate gyrus, and within the temporal lobes. The basal ganglia are associated with movement, cognition, emotions, and learning. There are two sets of basal ganglia in the brain, one in the right hemisphere and one in the left. The basal ganglia are comprised of a series of circuits that project to specific nuclei within the basal ganglia. The largest group of these nuclei is called the corpus striatum. The corpus striatum is made up of the caudate nucleus, the putamen, the globus pallidus, and the nucleus accumbens.
The caudate nucleus sends messages to the frontal lobe and is responsible for informing one that something is not right and that one should formulate a proper action to fix the problem. Obsessive compulsive disorder is a result of an overactive caudate, whereas ADD, depression, and lethargy are all results of an underactive caudate. The putamen is involved in coordinating automatic behaviors such as riding a bike. The globus pallidus receives inputs from the caudate and putamen and provides outputs to the substantia nigra which acts to facilitate the movement. The globus pallidus consists of two parts, globus pallidus externa and globus pallidus interna. Globus pallidus interna specifically deals with inhibiting all movements one will not do and defining the amplitude of the movement. The nucleus accumbens receives input signals in the form of dopamine from the prefrontal cortex and sends signals back through the globus pallidus.
The basal ganglia are responsible for all ballistic movements. Ballistic movements are open loop movements with no necessarily defined endpoint. These movements also help to modify voluntary movements. The basal ganglia select the movement by considering all possibilities and suppressing all but one, and scale the movement by regulating its amplitude. The motor functions of a human greatly rely upon the corpus striatum because it is the main input zone for other brain areas to connect to the basal ganglia. The circuit begins in the motor cortex which sends input to the basal ganglia via the striatum, then to the motor regions of the thalamus, and back to the motor cortex. What the motor cortex sends to the spinal cord depends on what occurs during the loop. In short, the basal ganglia inhibit the thalamus which in turn excites the cortex, causing movement. Inside the basal ganglia are two circuits. The first, the Direct Pathway, facilitates movement by disinhibition or inhibiting the inhibition. The Indirect Pathway discourages movement by inhibiting the globus pallidus externa, which inhibits the globus pallidus interna, which finally inhibits the thalamus which would have sent neurotransmitters to the motor cortex (inhibiting the disinhibition).
The substantia nigra is a very important part of the basal ganglia circuit because it releases dopamine which is a key toward facilitating the actual movement. It facilitates movement by releasing dopamine that excites the direct pathway and inhibits the indirect pathway. If the substantia nigra is damaged, one loses that ability to excite the direct pathway and inhibit the indirect pathway. In other words, one would lose the ability to amplify any movement one would like to make and inhibit any movement one would not like to make. Thus, both pathways are virtually dependent upon the substantia nigra.
Lesions in specific nuclei of the basal ganglia produce specific deficits. The most famous of which is Parkinson’s Disease which is the slow and pervasive loss of dopamine neurons in the substantia nigra. The symptoms of this disease are tremor, rigidity, and bradykinesia. Huntington’s disease is another example. This disease results from the degeneration of the caudate and putamen and produces continuous movements of the face and limbs.

Auguste D. (patient)

2008-04-05T22:41:34Z

Aterr:

[[Category:Neuropsychological profiles]]

Auguste Deter was born on May 16, 1850 in Cassel, Germany. She grew up in a protestant town of mostly home workers, small traders, and artisans who were eventually forced to assimilate into the Prussian empire in 1870. Her father died when she was relatively young and she had three siblings in her working class family. Auguste attended much school and according to research, was possibly a student of Alois Alzheimer’s grandfather, Johann. Auguste began working as either an assistant seamstress or in the ‘service’ for a middle class family when she was fourteen. In 1873 at the age of 23, Auguste married Karl Deter and moved to Frankfurt, Germany. Karl worked as a railway clerk and was in the Angestellte class and eventually they had a daughter, Thekla.

In 1901, Karl became concerned with a change in Auguste after she accused him of infidelity. After this event, Auguste began to neglect her housework, hide household objects, and make mistakes with her cooking. She declined rapidly and became restless, disturbing neighbors with her noise and paranoid ideas about others. In November 1901, Karl took Auguste to their family doctor who declared that with her symptoms of memory loss, mania, sleeplessness, restlessness, and inability to do mental or physical work, she should be committed to a mental institution. On November, 26, 1901, Auguste was admitted to the Municipal Asylum for the insane and epileptic, where Dr. Alois Alzheimer practiced.

During her time in the asylum, for the most part, she screamed loudly and exerted aggression towards others, but on rare occasions, she was courteous and kind towards others. Auguste spent most of her days in the bathtub (it was thought to soothe agitated patients) and most of her nights in the isolation room. Dr. Alzheimer kept her at this mental institution so he could study her, and Karl continued to struggle to pay her health fees and visit her as often as possible. By 1905, she was described as being completely bewildered, always in her bed, regularly soiling herself, and unable to feed herself. By the end of her life, she was constantly agitated, did not respond to sedatives, and was put in the bath every day. She developed sepsis and pneumonia and died on April 8, 1906.

Throughout Auguste’s time at the asylum, Dr. Alzheimer took on her case and studied her frequently. He took many notes on her diminishing memory and eventually described her as showing progressive cognitive impairment, focal symptoms, hallucinations, delusions, and psychosocial incompetence. He referred to her symptoms as senile dementia of the Alzheimer type which later became known as Alzheimer’s disease. Auguste D. became the first person diagnosed with Alzheimer’s disease.

Rey-Osterreith complex figure

2008-04-05T21:17:21Z

Aterr:

Blindsight

2008-04-05T20:35:02Z

Aterr:

[[Category:Neuropsychological syndromes]]

Blindsight is an extraordinary neuropsychological phenomenon that occurs after certain kinds of brain lesions, primarily in area V1, causing blindness. It is the ability to respond accurately (better than chance) to visual inputs given, without having the feeling or ability to see them. There are two types of Blindsight. The first type involves people that have no awareness of any objects projected into their blind region, but are able to correctly identify where the object is when pressed to do so. The second type of Blindsight involves people who have awareness of movement in their blind visual field, and are able to accurately ‘guess’ where the object is located.

The primary visual cortex is used for conscious vision. Damage to area V1, where the primary visual cortex is located, causes blindness in the opposite visual field of the hemisphere in which the damage was done. For Blindsight to be understood, vision must be understood. Visual processing occurs when ganglion cells of the retina send axons through the optic nerve to the lateral geniculate nucleus. The lateral geniculate nucleus is located in the thalamus and is a primary processor of visual information. It receives the visual information and then projects it to the primary visual cortex, or V1. Information from V1 is then sent to the secondary visual cortex and onto the occipital areas of the ventral and dorsal streams. The dorsal stream projects to the parietal lobe and the ventral stream sends information to the temporal lobe. Damage to the dorsal stream(area’s V3 and V5) causes cerebral akinetopsia (V5) and Balint’s syndrome. Damage to the ventral stream (area’s V4 and V8) causes cerebral achromotopsia (V4) and visual agnosia (V8). Thus it is clear that when there is damage to V1, the visual information processing stream is interrupted and visual deficits result. It is hypothesized that Blindsight and normal vision are controlled by other sections of the brain as a backup to the primary visual cortex. The superior colliculus, for instance, has been proven to take over some of the functions of the primary visual cortex. The superior colliculus supplies blindsighted individuals with the intrinsic feeling of where the object is in their blind visual field. It is used as a reflex for orienting eye and head movements towards something that is seen or heard. The only brain region though that allows for complete sight, local orientation, spatial frequency, and color properties within small receptive fields, is the primary visual cortex.