Psy3241 - User contributions [en]

Synesthesia

Emartinez — Mon, 05 May 2008 06:07:37 GMT

Emartinez:

[[Category:Neuropsychological syndromes]]

Synesthesia is a neurological syndrome in which stimulation of one sensory modality automatically and uncontrollably triggers another sensory modality. The types of synesthesia discussed in class include:

#Color-graphemic synesthesia: written letters induce vivid color experiences
#Colored-hearing: color experiences induced by spoken words
#Numbers are projected into a spatial layout in front of the patient's chest, and are colored
#Periods of time are conceptualized in a colored spatial layout

Synesthesia often begins in early childhood, but it can be brought about as a result of brain injury or sensory dedeafferentation.

Most of the time, synesthesia is unidirectional (for example, most colored-hearing synesthetes do not hear sounds when they see colors). Even if patients have the same form of synesthesia, it is unlikely that their concurrents are the same: letters will not necessarily produce the same colors to different synesthetes.

== Color-graphemic ==

[[image:synesthesia.png|250px|thumb|How somebody with color-graphemic synesthesia may read words and numbers]]

In Color-graphemic synesthesia, written words, letters, and numbers induce vivid color experiences. The actual experience of color tends to vary from patient to patient. Patients may report any of the following:

#As seen in the image, perceiving letters and numbers as being colored rather than monochrome (black).
#Seeing certain letters/words/numbers may cause the patient to see a screen of color "projected" onto their "mind's eye."
#As above, but rather than being fully colored, the screen is a blurry and colored version of the letter they are seeing.
#Patients may simply have an association between colors and letters/words/numbers without actually having a visual perception of color.

Sperling et. al (2006) found evidence that color-graphemic synesthesia is caused by an activation in the color areas ([[V4]]/V8) in the visual cortex as well as the inferior temporal lobe, another region known to be a cortical color processing system. A possible explanation for perceiving colors when seeing writing can be derived from activation of the superior temporal lobe and insula, which are hypothesized to mediate pathway convergence during the induction of a synesthetic-colour experience, leading to feedback-activation of visual areas responsible for color perception.

== Colored-hearing ==

In colored-hearing synesthesia, sounds produce an extrasensory experience of color. This is usually in response to tones or other aspects of sound. The sounds that produce colors in colored-hearing synesthetes are musical sounds or environmental sounds (such as alarm clocks, or birds chirping). As with color-graphemic synesthesia, activation in V4/V8 has been associated with the experience of color in response to music or environmental sounds.

== Number → Color & Shape ==

In (number)→(color/shape) synesthesia, the patient will project numbers in front of themselves in, for example, a colored arc.

== Time → Location ==

In (time)→(location) synesthesia, the patient will arrange periods of time in a colored shape. For example, they may conceptualize the months of the year into a flat, horizontal loop surrounding them in which each month has its own color.
== Causes ==

It is believed that synesthesia may have a genetic link, according to a twin study done by Hancock (2006). Hancock observed monozygotic twins, who both had color-number associations. The boys did not report seeing colors or even perceiving color experiences but, rather, had a simple association between numbers and colors, as if the numbers ''could be'' represented by colors. The genetic link was made possible by the discovery that the boys' mother also has a color-number association.

Synesthesia can also be a learned association. Witthoft and Winawer (2006) describe a case study in which their patient had a learned color-letter association as a byproduct of having colored refrigerator magnets as a child. Interestingly enough, this case also described the possibility that synesthetic color-letter associations can transfer between letters; their patient moved to Russia at the age of three, and her color-graphemic synesthesia transferred to Russian Cyrillik.

Alternatively, synesthesia may arise through "disinhibited feedback" or a reduction in the amount of inhibition along feedback pathways. Normally, the balance of excitation and inhibition are maintained. However, if normal feedback were not adequately inhibited, then signals coming from later multi-sensory stages of processing might influence earlier stages of processing, such that tones would activate visual cortical areas in synesthetes more than in non-synesthetes. In this case, it might explain why some users of psychedelic drugs such as LSD or mescaline report synesthetic experiences while under the influence of the drug.

== References ==

Grossenbacher, P.G., & Lovelace, C.T. (2001). Mechanisms of synesthesia: Cognitive and physiological constraints. ''TRENDS in Cognitive Sciences, 5''(1), 36-41.

Hancock, P (2006). Monozygotic twins’ colour-number association: A case study. ''Cortex, 42'', 147-150.

Sperling, J. M., Prvulovic, D., Linden, D.E.J., Singer, W., & Stirn, A. (2006). Neuronal correlates of a colour-graphemic synaesthesia: A fMRI study. ''Cortex, 42'', 295-303.

Witthoft, N., & Winawer, J. (2006). Synesthetic colors determined by having colored refrigerator magnets in childhood. ''Cortex, 42'', 175-183.

== External Links ==

[http://youtube.com/watch?v=DvwTSEwVBfc Tasting Colors]

Event related potentials

Emartinez — Fri, 25 Apr 2008 08:27:38 GMT

Emartinez:

[[Category:Neuropsychological methods]]
'''Event related potentials''' are electrical properties of biological cells and tissues reacting to an internal or external stimulus. Electrodes are attached to the scalp and the electrical activity is the amplified and deteced on a computer screen. The activity of neurons closest to the electrodes are being recorded in order to record the effect of the ERP (could be a tone or light flash). strong responses in the Visual cortex may indicate of a person with healthy a visual system. The ERP recordings show the timing it takes for the brain to communicate the information being process in this case the stimuli. ERP techniques have been found useful in finding information on attention.

'''Case'''
In a case testing split-brain patients, they had to decide whether pairs of pictures showed briefly and at the same time to right and left visual field represented same or different people. ERP's showed that inter-hemispheric transfer takes no more than 20 miliseconds.

'''Picture'''
[[http://www.nature.com/nrn/journal/v8/n8/images/nrn2195-f3.jpg]]

Prefrontal cortex

Emartinez — Fri, 25 Apr 2008 08:26:49 GMT

Emartinez:

[[Category:Brain areas]]

The '''Prefrontal Cortex''' (PFC) is the very front of the brain, located right beneath the forehead. It is in the anterior (front) region of the frontal lobes. The PFC is believed to have the most activity in a human, mainly because it contains the behavior of executive functions, which include mediating conflicting thoughts, making choices between right and wrong or good and bad, predicting future events, and governing social control -- such as suppressing emotional or sexual urges.

'''Areas'''

- lateral prefrontal cortex seems to help us choose a course of behavior by letting us evaluate the various alternatives mentally.

- orbitofrontal cortex seems to let us reschedule certain immediate pleasure and contain certain emotions in order to obtain greater long-term benefits.

-ventromedial cortex is thought to be one of the sites in the brain where we experience emotions and the meanings of things.

'''Cases'''

The most well known case having to do with the Prefrontal Cortex is the one of Phineas Gage, a railway worker whose prefrontal cortex was destroyed by a railroad spike. Following the accident, it is said that many of his earlier attributes vanished and he became a violent and aggressive person. there have also been studies that show that crimnals, drug addicts, and sociopaths have a weak interconnction of the PFC. These results give more evidence what responsibilities are contained in the PFC.
Just as we talk about dvelopmental disorders, for example a child without language never fully obtained it because it never developed the parts of the brain that make language possible. People unable to interpret reality, feel guilt, or make wrong moral choices do not develop or have parts that are damaged in the PFC.

'''Tests'''

Wisconsin Card Sorting Test

Trail Making

Reaction of choice tests (two choices)

Color and word page of Stroop Color and Word Test

'''Pictures'''

[http://www.wiredtowinthemovie.com/images/hotspots/level04prefrontalcortex.jpg]

[http://kybele.psych.cornell.edu/~edelman/Psych-231/Muzur02-figII.jpg]

Prefrontal cortex

Emartinez — Fri, 25 Apr 2008 08:13:54 GMT

Emartinez:

[[Category:Brain areas]]

The '''Prefrontal Cortex''' (PFC) is the very front of the brain, located right beneath the forehead. It is in the anterior (front) region of the frontal lobes. The PFC is believed to have the most activity in a human, mainly because it contains the behavior of executive functions, which include mediating conflicting thoughts, making choices between right and wrong or good and bad, predicting future events, and governing social control -- such as suppressing emotional or sexual urges.

'''Areas'''

- lateral prefrontal cortex seems to help us choose a course of behavior by letting us evaluate the various alternatives mentally.

- orbitofrontal cortex seems to let us reschedule certain immediate pleasure and contain certain emotions in order to obtain greater long-term benefits.

-ventromedial cortex is thought to be one of the sites in the brain where we experience emotions and the meanings of things.

'''Cases'''

The most well known case having to do with the Prefrontal Cortex is the one of Phineas Gage, a railway worker whose prefrontal cortex was destroyed by a railroad spike. Following the accident, it is said that many of his earlier attributes vanished and he became a violent and aggressive person. there have also been studies that show that crimnals, drug addicts, and sociopaths have a weak interconnction of the PFC. These results give more evidence what responsibilities are contained in the PFC.
Just as we talk about dvelopmental disorders, for example a child without language never fully obtained it because it never developed the parts of the brain that make language possible. People unable to interpret reality, feel guilt, or make wrong moral choices do not develop or have parts that are damaged in the PFC.

'''Pictures'''

[http://www.wiredtowinthemovie.com/images/hotspots/level04prefrontalcortex.jpg]

[http://kybele.psych.cornell.edu/~edelman/Psych-231/Muzur02-figII.jpg]

Roger Sperry

Emartinez — Fri, 25 Apr 2008 07:42:47 GMT

Emartinez:

[[Category:Neuropsychological profiles]]
'''Roger Wolcott Sperry'''
Roger Sperry (August 20, 1913 – April 17, 1994) was a neuropsychologist, neurobiologist and Nobel laureate who, with two fellow researchers, won the 1981 Nobel Prize in Medicine for his work with split-brain research.

Sperry was born and raised in Hartford, Connecticut. He was smart and talented enough that it earned him a scholarship to Oberlin College. He participated in sports and did well academically. He went on to graduate with an English degree, and soon would be back to earn his masters in psychology. Post masters, he went to the University of Chicago and earned his Ph.D in zoology.

Sperry did post-doctoral research with a well known psychologist Karl Lashley at Harvard University. After much research and experience teaching, he accepted a job as the prestigious Hixon professor of Psychobiology at California Institute of Technology in Pasadena (Caltech).

While at Caltech, Sperry pursued his interest in the routes by which information is transferred from one side of the cerebral cortex to the other. After a series of experiments, Sperry and his colleagues discovered two possible routes for such interhemispheric transfer—the corpus callosum and the optic chiasm. However, he found that ablating both the corpus callosum or the optic chiasm before training did not interfere with transfer. A brain that has had its corpus callosum and its optic chiasm ablated is referred to as a split-brain preparation.

The additional knowledge provided by Sperry and his colleagues was dramatic. They found that each hemisphere had its own characteristic range of cognition, memory, emotion, and consciousness. Sperry leading the way, Research on the “left brain” and the “right brain” became very popular. There were some controversies with this later on in his career but much research was done to prove otherwise. The left hemisphere is the one with speech, as had been known, and it is dominant in all activities involving language, arithmetic, and analysis. The right hemisphere, although mute and capable only of simple addition (up to about 20) is superior to the left hemisphere in, among other things, spatial comprehension--in understanding maps, for example, or recognizing faces.

In his lifetime, Sperry published almost 300 articles in the most prestigious journals and many of those articles were translated into several languages (Puente, 1995).

Sperry past away on April 17, 1994, in Pasadena, California. He was 80 years old and cause of death was a degenerative neuromuscular disorder (Puente, 1995).

'''Awards & Honors'''

Karl Lashley Award of the American Philosophical Society (1976)

The Wolf Prize in Medicine (1979)

The Ralph Gerard Award from the Society of Neuroscience (1979)

The Nobel Prize in medicine/physiology (shared with David Hubel and Torsten Wiesel) (1981)

The Lifetime Achievement Award from the APA (1993)

'''Personal Life'''

In 1949, Sperry married Norma Gay Deupree. They had one son, Glenn Michael, and one daughter, Janet Hope.

Event related potentials

Emartinez — Fri, 25 Apr 2008 07:32:03 GMT

Emartinez:

[[Category:Neuropsychological methods]]
'''Event related potentials''' are electrical properties of biological cells and tissues reacting to an internal or external stimulus. Electrodes are attached to the scalp and the electrical activity is the amplified and deteced on a computer screen. The activity of neurons closest to the electrodes are being recorded in order to record the effect of the ERP (could be a tone or light flash). strong responses in the Visual cortex may indicate of a person with healthy a visual system. The ERP recordings show the timing it takes for the brain to communicate the information being process in this case the stimuli. ERP techniques have been found useful in finding information on attention.

'''Case'''
In a case testing split-brain patients, they had to decide whether pairs of pictures showed briefly and at the same time to right and left visual field represented same or diffent people. ERP's showed that inter-hemispheric transfer takes no more than 20 miliseconds.

'''Picture'''
[[http://www.nature.com/nrn/journal/v8/n8/images/nrn2195-f3.jpg]]

Event related potentials

Emartinez — Fri, 25 Apr 2008 07:22:08 GMT

Emartinez:

Hemiplegia

Emartinez — Fri, 25 Apr 2008 06:52:34 GMT

Emartinez:

[[Category:Neuropsychological syndromes]]
'''Hemiplegia'''
Hemiplegia is defined as total or partial paralyses of one side of the body that results from disease of or injury to the motor centers of the brain.

'''Causes'''

Hemiplegia can be congenital, which is occurring before, during, or soon after birth, or acquired as from illness or stroke. The general cause of Hemiplegia is interruption of blood supply via the mid-celebral artery.
Can be due to: ''Aneurysm, Haemorrhage, Clot''

'''Improvements'''

Many time patients with Hemiplegia can get better. This is because hemiplegia can also affect adjacent neurons where activity ia affected by change in blood supply. In later stages these neurons can go back to normal level of functioning, helping the patient in achieving movement. Also different parts of the brain can learn to hadle body movements, after long periods of hemiplegia. Most children with congenital hemiplegia have a normal IQ and will attend mainstream school. Although language is usually well preserved (irrespective of which hemisphere is involved), specific learning difficulties are found in one-third and must be recognized early.

'''Overcoming Hemiplegia'''
[http://youtube.com/watch?v=u8GYJpySNRo]

References:
Striling, J. Introducing Neuropsuchology. New York. Psychology Press. 2002.

Hemiplegia

Emartinez — Fri, 25 Apr 2008 06:43:48 GMT

Emartinez:

Hemiplegia

Emartinez — Fri, 25 Apr 2008 06:39:37 GMT

Emartinez:

[[Category:Neuropsychological syndromes]]
'''Hemiplegia'''
Hemiplegia is defined as total or partial paralyses of one side of the body that results from disease of or injury to the motor centers of the brain.

'''Causes'''

Hemiplegia can be congenital, which is occurring before, during, or soon after birth, or acquired as from illness or stroke. The general cause of Hemiplegia is interruption of blood supply via the mid-celebral artery.
Can be due to: ''Aneurysm, Haemorrhage, Clot''

'''Improvements'''

Many time patients with Hemiplegia can get better. This is because hemiplegia can also affect adjacent neurons where activity ia affected by change in blood supply. In later stages these neurons can go back to normal level of functioning, helping the patient in achieving movement. Also different parts of the brain can learn to hadle body movements, after long periods of hemiplegia.

'''Overcoming Hemiplegia'''
[http://youtube.com/watch?v=u8GYJpySNRo]

Hemiplegia

Emartinez — Fri, 25 Apr 2008 06:38:35 GMT

Emartinez: