Chapter 9 part 2 Flashcards
How many visual areas are there in the occipital cortex?
at least 6
What are the visual regions in the occipital cortex?
Primary visual cortex
Secondary visual cortex (V2 to V5; extrastriate cortex)
What are two parts of the heterogeneous layering in V1?
Blobs and interblobs
What are blobs contain info about? What cells do they get info from?
P-cells and contains colour sensitive neurons
What are interblobs contain info about? What cells do they get info from?
M-cells
Perception of form and motion
Where is segregation of information about colour, form and motion maintained?
V1 and V2
What are the three parts of of V2?
Thin stripes, thick stripes and pale zones
Where do thin stripes receive info from?
colour sensitive neurons (blobs)
Where do thick stripes receive info from?
movement sensitive neurons in interblobs
Where do pale zones receive info from?
Form-sensitive neurons from interblobs
Describe the visual stream for colour information?
Blobs –> thin stripes (V2) –> V3 and V4 –> temporal lobe (ventral stream)
Describe the visual stream for movement information?
interblobs –> thick stripes –> V3A and V5 –> parietal lobe (dorsal stream)
Describe the visual stream for form information?
interblobs –> pale zones –> ventral and dorsal stream
What is the function of the pulvinar?
Directs spatial attention
What is a visual field?
Total area in which objects can be seen when eyes are fixed on a point
What is a receptive field?
Area of the visual field that photoreceptors respond to
Do receptive fields get larger in higher order neurons? What is it useful for?
Yes. Coding location
What do retinal ganglion cells detect?
local contrast in light intensity
What happens when you shine light across the entire receptive field of an on center cell?
Weak excitation
What happens when you shine light across the entire receptive field of an off-center cell?
Weak inhibition
How are RGC receptive fields positioned in real life?
They all overlap
What do RGC tell the brain?
about the amount of light hitting a certain spot relative to the average in the surrouding area
What is luminance contrast?
The amount of light reflected by an object relative to its surroundings
Do receptive fields in LGN maintain same spatial relationship as RGCs?
yes
