physiology of visual cortex Flashcards
how does info get to the primary visual cortex?
from the lateral geniculate nucleus, which received info from the eyes
two pathways from lateral geniculate nucleus to primary visual cortex
1) superior pathway - terminates above calcarine sulcus
2) Meyer’s Loop - goes around lateral ventricle and terminates below calcarine sulcus
upper half of visual field goes to
below calcarine sulcus to Meyer’s loop
lower half of visual field goes to
above calcarine sulcus
an injury to an eye or optic nerve can result in:
monocular blindness
damage (pituitary tumor) to optic chiasm could result in
bitemporal hemianopia, nasal retinas lose function
damage to a lateral geniculate could result in
homonomous hemianopia
V1 cells
simple cortical cells - line
complex cortical cells - end of line
hypercomplex cortical cells - movement
V2/V3 location and function
occipital lobe, depth perception
V4 location and function
occipital lobe, color
V5 location and function
middle temporal, motion detection, spatial
relationships, depth perception
general dorsal pathway, route and function
- V1 - V2 - V5 - parietal lobe
- motion, depth perception, relative size
general ventral pathway, route and function
- V1 - V2 - V4 - temporal lobe
- object and form recognition
a lesion of the dorsal pathway can cause:
- motion blindness (akinetopia)
two types of depth perception
1) stereopsis - position on retina, for objects less than 100 ft away
2) monocular - greater than 100 ft away, based on previous familiarity, relative size, etc.
