Psy3241 - User contributions [en]

Primary visual cortex (V1)

Wely — Tue, 29 Apr 2008 01:35:39 GMT

Wely:

[[Category:Brain areas]]
Primary Visual Cortex V1

http://scien.stanford.edu/class/psych221/projects/06/cukur/intro_files/image021.jpg

The Primary Visual Cortex or V1 is located in the posterior pole of the occipital lobe, which is the area for processing visual stimuli. V1 is fairly simple with 6 layers that each has their own functional responsibility. The primary visual cortex is very specialized itself in processing information about subject movement and recognizing patterns.

The function of the primary visual cortex is providing a well-defined map of the spatial information in vision as it receives its information direct from the lateral geniculate nucleus (LGN). LGN is the primary processor of visual information as it receives its information from the retina and then sends it directly to the primary visual cortex. When comparing the V1 to the subject’s visual field there is a strong correspondence between the two. Evidence of this is the precise location of blind spots being mapped in the V1 area compared to the blind spots in the subject’s visual field.

The primary visual cortex is very important as it the origin of information for two primary pathways. The first pathway is the dorsal stream, which begins with V1, goes through V2 and V5, and to the posterior parietal cortex. The dorsal stream is important as it provides information on where an object is including motion, location of the object, and control of the eyes and arms. This is important as it allows proper reaching and contact with objects to be executed.

The second pathway is the ventral stream and it begins with V1, into V2 and V4, and ends at the inferior temporal cortex. This pathway deals with processing of what an object is. It utilizes information with form recognition, object representation, and with storage of long-term memory. All this information is used to identify, recognize, and remember objects.

Damage and lesions to the primary visual cortex can severely impair visual function. The main ability of the V1, which is affected by a lesion, is visual motion perception. This strongly relates to the dorsal pathway, which the V1 provides information about motion for visual perceptual abilities.
Lesions in the primary visual cortex also can create blind spots in the corresponding region of the visual field.

Kim et al. (2006)

Wely — Tue, 29 Apr 2008 01:32:27 GMT

Wely:

[[Category:Synesthesia Symposium]]
'''Perceptual Interaction Between Real And Synesthetic Colors'''
In this article the perceptual interaction between real and synesthetic colors is examined using participants with color-graphemic synesthesia. People with color-graphemic synesthesia experience consistent and vivid colors after viewing achromatic alphanumeric characters. This article looks at the issues of how real and synesthetic colors interact, and how synesthetes see the real and concurrent synesthetic color at the same time. Other issues include how one can see two colors in the same location, and what the relationship is between synesthesia and imagery.

In the first experiment, the influence that real and synesthetic colors play on the perceived direction of apparent motion was examined. In the interaction condition, the first frame was shown which was non-inducing, and physically colored. SHortly after a second frame was shown which was achromatic with different characters. The results showed that synesthetes were experiencing the illusion of motion as the first frame had real red objects in it and the second frame had synesthetically red colored objects which gave them the illusion of motion they were seeing.

In the second experiment, the interaction between real and synesthetic colors that results in binocular rivalry was examined. Binocular rivalry is when two different images compete for perceptual dominance. In this experiment they were looking for the rivalry between real and synesthetic colors. In the interaction condition both LR and WO perceived the real color and synesthetic color during binocular rivalry. This observation of the grouping of real and synesthetic colors together was comparable to the grouping between synesthetic colors and the grouping of actual colors.

The results show that their is a significant interaction between the real and synesthetic colors during perceptual grouping. Also, the interaction between real and synesthetic colors result in a perception in specific motion and character grouping. [http://blackboard.rollins.edu/courses/1/10301.PSY324.1.200801/content/_176453_1/Kim_2006_interaction_real_synesthetic_color.pdf Link to article]

Kim et al. (2006)

Wely — Tue, 29 Apr 2008 01:29:24 GMT

Wely:

[[Category:Synesthesia Symposium]]
In this article the perceptual interaction between real and synesthetic colors is examined using participants with color-graphemic synesthesia. People with color-graphemic synesthesia experience consistent and vivid colors after viewing achromatic alphanumeric characters. This article looks at the issues of how real and synesthetic colors interact, and how synesthetes see the real and concurrent synesthetic color at the same time. Other issues include how one can see two colors in the same location, and what the relationship is between synesthesia and imagery.

In the first experiment, the influence that real and synesthetic colors play on the perceived direction of apparent motion was examined. In the interaction condition, the first frame was shown which was non-inducing, and physically colored. SHortly after a second frame was shown which was achromatic with different characters. The results showed that synesthetes were experiencing the illusion of motion as the first frame had real red objects in it and the second frame had synesthetically red colored objects which gave them the illusion of motion they were seeing.

In the second experiment, the interaction between real and synesthetic colors that results in binocular rivalry was examined. Binocular rivalry is when two different images compete for perceptual dominance. In this experiment they were looking for the rivalry between real and synesthetic colors. In the interaction condition both LR and WO perceived the real color and synesthetic color during binocular rivalry. This observation of the grouping of real and synesthetic colors together was comparable to the grouping between synesthetic colors and the grouping of actual colors.

The results show that their is a significant interaction between the real and synesthetic colors during perceptual grouping. Also, the interaction between real and synesthetic colors result in a perception in specific motion and character grouping.

Kim et al. (2006)

Wely — Tue, 29 Apr 2008 01:20:39 GMT

Wely:

Kim et al. (2006)

Wely — Tue, 29 Apr 2008 01:10:33 GMT

Wely:

Kim et al. (2006)

Wely — Tue, 29 Apr 2008 01:05:38 GMT

Wely:

Kim et al. (2006)

Wely — Tue, 29 Apr 2008 01:02:04 GMT

Wely:

Giraud et al. (2001)

Wely — Mon, 28 Apr 2008 23:39:59 GMT

Wely: /* Cross-Modal Plasticity Underpins Clinical Study Language Recovery after Cochlear Implantation */

[[Category:Plasticity Symposium]]

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== Cross-Modal Plasticity Underpins Clinical Study Language Recovery after Cochlear Implantation ==

Basically, in this study the cochlear implants restored hearing to the deaf participants by stimulating the auditory nerve with about sixteen electrodes. Cochlear patients must work hard to hear, mainly because their sound signal is usually deteriorated. After the procedure the patients take a while to get accustomed to their new hearing devices. In the time after their implant, patients must rely on lipreading in order to understand what they are hearing because their implant is unable to discriminate similar sounding words (i. e. duck/buck). Therefore, after a period of time in which the patient is lipreading to comprehend, visual cortex begins to activate when patients listen, even in purely auditory tasks (eyes closed). The amount of activity in the visual cortex was dependent on the amount of time the patient had their implant. The longer the time, the greater the amount of visual cortex activity when listening.
[http://blackboard.rollins.edu/courses/1/10301.PSY324.1.200801/content/_175427_1/Giraud_2001_Human_cochlear_implant_Neuron.pdf Link to the actual article by Giraud et al.]
[http://www.pbs.org/saf/1205/features/Interactive/intro1.htm WHAT IT'S LIKE TO HEAR WITH A COCHLEAR IMPLANT] [http://www.pbs.org/wnet/soundandfury/index.html Background info on cochlear implants]
----
[[Image:Implant_works.jpg]]

Giraud et al. (2001)

Wely — Mon, 28 Apr 2008 23:37:51 GMT

Wely:

[[Category:Plasticity Symposium]]

----

== Cross-Modal Plasticity Underpins Clinical Study Language Recovery after Cochlear Implantation ==

Basically, in this study the cochlear implants restored hearing to the deaf participants by stimulating the auditory nerve with about sixteen electrodes. Cochlear patients must work hard to hear, mainly because their sound signal is usually deteriorated. After the procedure the patients take a while to get accustomed to their new hearing devices. In the time after their implant, patients must rely on lipreading in order to understand what they are hearing because their implant is unable to discriminate similar sounding words (i. e. duck/buck). Therefore, after a period of time in which the patient is lipreading to comprehend, visual cortex begins to activate when patients listen, even in purely auditory tasks (eyes closed). The amount of activity in the visual cortex was dependent on the amount of time the patient had their implant. The longer the time, the greater the amount of visual cortex activity when listening.
[http://blackboard.rollins.edu/courses/1/10301.PSY324.1.200801/content/_175427_1/Giraud_2001_Human_cochlear_implant_Neuron.pdf Link to the actual article by Giraud et al.]
[http://www.pbs.org/saf/1205/features/Interactive/intro1.htm WHAT IT'S LIKE TO HEAR WITH A COCHLEAR IMPLANT] [http://www.pbs.org/wnet/soundandfury/index.htm Background info on cochlear implants]
----
[[Image:Implant_works.jpg]]

Primary visual cortex (V1)

Wely — Mon, 28 Apr 2008 23:25:11 GMT

Wely:

[[Category:Brain areas]]
Primary Visual Cortex V1

The Primary Visual Cortex or V1 is located in the posterior pole of the occipital lobe, which is the area for processing visual stimuli. V1 is fairly simple with 6 layers that each has their own functional responsibility. The primary visual cortex is very specialized itself in processing information about subject movement and recognizing patterns.

The function of the primary visual cortex is providing a well-defined map of the spatial information in vision as it receives its information direct from the lateral geniculate nucleus (LGN). LGN is the primary processor of visual information as it receives its information from the retina and then sends it directly to the primary visual cortex. When comparing the V1 to the subject’s visual field there is a strong correspondence between the two. Evidence of this is the precise location of blind spots being mapped in the V1 area compared to the blind spots in the subject’s visual field.

The primary visual cortex is very important as it the origin of information for two primary pathways. The first pathway is the dorsal stream, which begins with V1, goes through V2 and V5, and to the posterior parietal cortex. The dorsal stream is important as it provides information on where an object is including motion, location of the object, and control of the eyes and arms. This is important as it allows proper reaching and contact with objects to be executed.

The second pathway is the ventral stream and it begins with V1, into V2 and V4, and ends at the inferior temporal cortex. This pathway deals with processing of what an object is. It utilizes information with form recognition, object representation, and with storage of long-term memory. All this information is used to identify, recognize, and remember objects.

Damage and lesions to the primary visual cortex can severely impair visual function. The main ability of the V1, which is affected by a lesion, is visual motion perception. This strongly relates to the dorsal pathway, which the V1 provides information about motion for visual perceptual abilities.
Lesions in the primary visual cortex also can create blind spots in the corresponding region of the visual field.

Walter Freeman

Wely — Thu, 24 Apr 2008 03:14:07 GMT

Wely:

[[Category:Neuropsychological profiles]]
Dr. Walter J. Freeman was a physician and psychosurgeon who was known for his popular neurosurgical procedure, the lobotomy. He studied at Yale University and then attended the University of Pennsylvania Medical School.

During his career he performed thousands of lobotomies and it soon became a well-known procedure of psychosurgery. Freeman started out performing the lobotomies with other surgeons, with the first procedure in 1936. He then continued performing the procedure with other surgeons and alone, but with other forms of treatment, like the antipsychotic Thorazine, replacing the lobotomy it was slowly becoming less popular. In 1967 one of Walter’s patients died from the surgery and his career was ended as he was no longer allowed to perform the procedure.

A lobotomy is a psychosurgery that destroys the connections to the prefrontal cortex. This procedure is mainly performed on patients that need treatment for severe mental illness including schizophrenia, clinical depression, and anxiety disorders.

Freeman is also well known for his ice pick, which is used in the transorbital lobotomy. While seeking a faster way to perform the procedure Freeman decided to use an actual ice pick which was used to be pushed through the back of the eye socket into the brain. Later, the ice pick was replaced by the leucotome, an instrument designed for the procedure, and then replaced again by the orbitoclast, a stronger instrument designed by Freeman.

Freeman’s lobotomy procedure began to spread as he toured the nation in his van, called the “lobotomobile,” to train and educate surgeons in the procedure. During this time there was a lack of effective treatments. Freeman saw this as a chance to allow the transorbital lobotomy to be used to treat patients and reduce the overwhelming amount of people looking for treatments. Many people criticized Freeman for being a sociopath who enjoyed performing the procedure. Then in the 1950’s Thorazine and other psychotropic drugs became favored over the lobotomy. Although his license to practice medicine was take away, many of his patients continued to live long peaceful lives and remained friends with Freeman.

Computed tomography

Wely — Mon, 21 Apr 2008 22:54:25 GMT

Wely:

[[Category:Neuropsychological methods]]
A computed tomography scan, also known as CT, takes detailed X-ray images of the different structures inside of the body. During the test the patient lies on the table while the CT scanner, a large circular machine sends X-rays through the area of the body being studied. To allow the image to be clear, an iodine dye is used sometimes to produce an image with more contrast and detail.

A computed tomography scan is mainly used for the chest, belly, pelvis, or the arms and legs. Scans are also common for body organs, but can also take images of blood vessels, bones, and the spinal cord.

CT scans are very helpful to study the brain as they can show cross-sectional views. The use of CT scans in studying the brain is to allow detection of hematomas, tumors, and strokes.

User:Wely

Wely — Mon, 21 Apr 2008 22:53:50 GMT

Wely:

Billy Ely

Gerstmann's syndrome

Wely — Tue, 15 Apr 2008 01:38:46 GMT

Wely:

[[Category:Neuropsychological syndromes]]

Gerstmann’s syndrome is a neurological disorder named after the Austrian neurologist, Josef Gerstmann. This disorder is not unique to itself but instead is classified by four primary syndromes that include a writing disability, a lack of understanding of the rules for calculation or arithmetic, inability in distinguishing right from left, and the inability to identify fingers. Other possible symptoms include the difficulty in expressing oneself while speaking, reading and writing, and understanding speech, which is known as aphasia.

Gerstmann’s syndrome is mainly caused either by a stroke or damage to the brain in the parietal lobe on the dominant side at the angular gyrus. In adults, this syndrome will decrease overtime but for children the chance of the symptoms decreasing in severity is less likely. This is because of the syndrome occurring from congenital or learning disorders in the children. Also there are no treatments for Gerstmann’s syndrome at this time.

The first main symptom is agraphia, which is a writing disability. This is usually diagnosed by illegible or very poor writing, inconsistencies in forming letters, mixture of upper and lower case letters, mixture between print and cursory writing, irregular letter sizes and shapes, and unfinished letters.

Acalculia is the lack of understanding of the rules for calculation or arithmetic. To test the patient a task of serial subtraction of 7 from 100 is to be completed. This means they start at 100 and count down to 93, 86, 79, 72, etc.

Finger agnosia is the inability to identify fingers on the hand. This is tested by asking the patient to use a specific finger to touch another specific finger or other various body parts. An example would be to use your right index finger to touch your nose.

The last symptom is left-right disorientation, which is the confusion between your left and right limbs. This is important as it shows there is a lesion in the dominant parietal lobe. Tests for left-right disorientation involve the patient being asked questions involving left and right body parts and whether they can accurately obey the commands.