Slide 2 Flashcards
What is the major visual info processing pathway
retina geniculate striate pathway
what percent of axons leaving the retina use this pathway?
90 %
Name the 2 portions of the retina which cover diff parts of the visual system
- temporal hemi-retina
- nasal hemi-retina
Describe the left visual field
- nasal retina
- from left side
- crosses
- temporal retina
- from right side
- does not cross
What is the optic chiasm
where axons coming from nasal retina cross
What is the lateral geniculate nucleus?
- thalamic nucleus
- relays visual info
- from retina
- to visual cortex
What is the striate cortex?
primary visual cortex (aka V1)
Info from left visual field goes to ____ V1
Info from right visual field got to _____ V1
- right
- left
True or false: in the lateral geniculate striate pathway there are both ipsilateral and contralateral projections
true
From where do P channels get majority of info?
cones
What do P channels respond to
- color
- fine details
From where do M channels get majority of info?
rods
What do M channels respond to
-movement
Where is the striate cortex located
- deep in occipital lobe
- around calcarine fissure
Where does the first stage of viusal processing occur in the cerebral cortex
V1 (striate/visual cortex)
How many layers of cells does the V1 have
6
Which layer does the lateral geniculate nucleus project to?
4th layer
Describe organization of the visual cortex and lateral geniculate nucleus
- topographical
- retinotopic organization
What is retinotopic organization?
organized like a map of the retina
Which part of the retina receives a large representation in retinotopic organization?
fovea
Evidence for retinotopic organization
image is imprinted on the visual cortex
What is the receptive field
- area of visual field
- within which it is possible
- for visual stimulus
- to influence activity of a given neuron
True or false: receptive fields come in diff shapes
true
Who were the scientists who studied receptive field
hubel and wiesel
