visual paths central pathways Flashcards
visual system retina to striate cortex
optic nerve to optic chiasm to optic tract to Lateral geniculate body (in thalamus) to optic radiation (lower and upper) to striate area of visual primary cortex
Lateral geniculate nucleus
layers are segregated
Magnocellular layer: large cells that recieve input from parasol ganglion cells
Parvo cellular: small cells and receive input from midget cells
retinotopy of primary visual cortex
macula densa represents the majority of the striate cortex, mostly burried in the calcarine sulcus
unilateral optic nerve lesion
blindness of affected eye only
lesion down the center of the optic chiasm
causes bilateral hemianopia
(nasal portions of retina cross over in the optic chiasm and the nasal portion of the retina collects info from the temporal visual fields)
unilateral optic tract lesion
causes contralateral homonymous hemianopia
cuts off the lateral retina of the ipsilateral eye- nasal visual field of that eye destroyed
cuts off the nasal retina of the contralateral eye- temporal visual field of that eye
unilateral lesion of optic radiation in anterior temporal lobe (meyers loop)
contralateral upper quadrantanopia
unilateral lesion in medial part of optic radiation in parietal lobe (meyers loop)
contralateral lower quadrantanopia
occipital lobe lesion
homonymous hemianopia with macular/foveal sparing
occipital pole lesion
central macular homonymous hemianopia
superior colliculus
mesencephalic, recieves input from parosal cells-> controls head and nucleus, orieting stimulus
extrastriate cortex
brodmans 17 - striate cortex
Area 4- motor area
V4- color discrimination (achromatopsia) in temporal what is it
V5/MT- detection of motion (snapshot- akinetopsia)in parietal where is it
V1 projects to V2
downstream from V4 is the ventral stream in the temporal lobe and it recognizes faces
