Striate+Cortex+-+Primary+Visual+Receiving+Area

Broadmann's area 17

Predominantly within the medial walls of the cerebral hemispheres, extending only minimally along the lateral convexity. This area is often referred to as "striate" because the incoming fibers from the optic radiations form a stripe along the cortical surface which can be seen by the naked eye. Areas 18 and 19 do not have this striped appearance.
 * Location**

-Analysis of color -Slow movement -Position -Orientation i.e. the most elementary aspects of form and visual stimulus perception.
 * Primary Functions **

Rather thin cortical layers, particularly layers II and II, and by its striped appearance which is due to the structure and composition of layer IV. Layer IV is divided into three sublayers, with the middle layer containing a rather thick band of cortex (the band of Baillarger/Gennari) which is visible to the naked eye.
 * Cortical Structure **

Like the primary motor and somesthetic cortices, a greater degree of cellular representation is maintained for those areas which are the most densely innervated and of the most sensory importance, i.e., the fovea. ( most sensitive to the detection and representation of form) The central part of the retina has a cortical representation which is 35 times more detailed than that of the periphery.

Although all neuron types are found within the striate cortex, simple and complex cells predominate.

<span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">-Brainstem nuclei <span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">-Pontine <span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">-Mesencephalic reticular formation <span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">-Lateral amygdala <span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">-Lateral hypothalamus
 * Connections from**

<span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">Processing in the primary region can thus be enhanced or diminished via reticular influences and emotional-motivational concerns. In this manner, if a stimulus is emotionally significant greater visual attention will be directed at the object.

<span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">Bilateral destruction: can result in loss of visual recognition capabilities -even with sparing of the association areas. Awareness of moving objects and visual-spatial orientation is preserved. <span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">Visual preservation with primary occipital destruction has been referred to as "blind sight"
 * Damage:**

<span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">Electrical stimulation, tumors, seizures, or trauma involving the striate cortex may produces simple visual hallucinations <span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">-Sparks <span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">-Tongues of flames <span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">-Colors and flashes of lights <span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">-Objects may seem to become exceedingly large (macropsia) or small (micropsia) <span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">-Blurred in terms of outline <span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">-Stretched out in a single dimension <span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">-Colors may become modified or even erased <span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">-Sometimes simple geometric forms may be reported.
 * Hallucinations**

<span style="font-family: 'Times New Roman',serif; font-size: 11pt; line-height: 1.5;">Usually the hallucination is restricted to one half of the visual field. That is, if the seizure is in the right occipital lobe, the hallucination will appear in the left visual field.

<span style="font-family: 'Times New Roman',serif; font-size: 11pt;">Although elementary hallucinations are usually associated with abnormalities involving the occipital lobe they may occur with temporal lobe lesions or electrical stimulation.