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Flashcards in visual pathways Deck (11):

how can rods join the cone pathways

via amacrine cells


what are the five projections of the optic tracts

dLGN, superior colliculus, accesory optic nuclei, pretectal area, SCN


what do melanopsin retinal ganglion cells do

signal light levels. Pretectal and SCN paths


difference b/w melanopsin containing and rods and cones

depolarize in response to light and lasts as long as the stimulus withough adaptation


efferent limb failure

failure of one pupil to constrict when light is shined in eigher eye, with normal constriction of other pupil


why do you get preserved near response in MLF syndrome

b/c the third nucleus doesnt get gaze command but it does get near response command


deficit seen in LGN lesion

slightly non-corresponding (almost homonymous) deficits due to laminar segregation.


where do you see exactly corresponding visual field deficits

occipital cortex


route of upper field information. Lower field information

through meyer's loop to lower bank of calcarine fissure. Parietal path to upper bank


Extrastriate lesions: temporal, parietal, occipito-temporal

loss of recognition and memory; visual inattention and neglect; loss of recognition of faces


rule of thumb for localizing lesions: the more homonymous, the more ___ the lesion. The higher in the upper field, the more ___ the lesion

posterior; lateral