Primary visual cortex (V1)

From Psy3241

Primary Visual Cortex V1

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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.

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