Lecture 30- Extrastriate Cortices Flashcards
Which visual field do cells on the superior bank of the clacarine sulcus respond to?
Cells on the superior bank of the calcarine sulcus respond to signals in the lower visual field (inverted)
Where is the “stripe of Gennari” located within the cortex?
layer 4B
What accounts for the white stripe seen in the primary visual cortex?
the presence of large amounts myelin in layer 4B of the cortex
Where do the visual inputs from the lateral geniculate nucleus (LGN) project to in the primary visual cortex?
Layer 4 of the Striate (primary visual cortex)
Where do neurons from layer 4 of the striate cortex project?
back to the LGN
Where do neurons of layer 5 of the striate cortex project?
superior colliculus
What happens if the entire primary visual cortex on one side is lesioned?
homonymous hemianopia- unable to detect or respond to stimuli in the contralateral visual field
What accounts for the blindsight phenomenon seen in patients with destruction of the primary visual cortex?
ascending projection from the superior colliculus to the pulvinar nuclueus of the thalamus that allow for detection of large and moving stimuli
What are the two types of cells of the primary visual cortex?
parvocellular and magnocellular
What are parvocellular ganglion cells of the primary visual cortex also known as?
midget cells
What are magnocellular cells of the primary visual cortex known as?
parisol cells
What types of stimuli are parvocellular (midget) cells more receptive to?
color, high contrast detail
What types of stimuli are magnocellular (parasol) cells more receptive to?
quick changes/movement
Where do the magnocellular LGN neurons project?
the upper part of layer 4C (4C alpha)
Where do the parvocellular LGN neurons project?
the lower part of layer 4 C (4C beta)
