W3_lec2 Flashcards
They say basic visual features are processed hierarchically what does this mean?
we analyze visual features from their simplest forms to their most complex as they proceed up the hierarchy
What are the 3 cortices that are associated w/ the processing hierarchy?
- occipital cortex
- parietal cortex
- inferotemporal cortex
Describe the 2 visual stream pathways.
- ventral stream = Extracts shape and textural info in order to identify objs (occipital cortex –> interior temporal cortex)
- dorsal stream = processes relevant spatial info in order to guide action (occipital cortex –> parietal cortex)
Match the following terms
a) damage to dorsal
b) dorsal stream
c) ventral stream
d) damage to ventral
1. where
2. what
3. DF
4. VF
a) 4
b) 1
c) 2
d) 3
the Dorsal and the Ventral pathways are an example of a _____________. This is b/c the damage of one stream has no effect on the fxn of another and visa versa
double disassociation
ANS the following wrt Visual agnosia
a) DF or VF
b) what does it do?
c) where is the damage?
d) provide and experiment
a) DF
b) unable to identify visual objs
c) ventral stream
d) orientating the envelope to match the slit in the mailbox. They were unable to match it properly but could when told to just place the envelope in the mailbox
ANS the following wrt Optic Ataxia
a) DF or VF
b) what does it do?
c) where is the damage?
d) provide and experiment
a) VF
b) unable to use visual info to guide behaviour
c) dorsal stream
d) going to pick up a pog (small disk) while measuring the changes in movement in the hand. They found that the participant was unable to gage the size of the pog as they opened their hand much wider then needed.
Match the following terms
a) Optic ataxia
b) Visual Agnosia
1. DF
2. Vf
a) 2
b) 1
a) What is the critical feature wrt the ventral stream - 2
b) What happens to the complexity of the neural representation so visual info as you travel from posterior regions to anterior regions - 1
c) What type of info does the inferior temporal cortex (IT) respond to? Why?
a) object identification - intersection b/w vision and memory
b) back to front - INC in complexity
c) complex visual info (house/face) b/c IT cells have a large receptive field
a) Is visual agnosia caused from damage in the ventral or the dorsal stream?
b) Describe the following kinds of visual agnosia
i) associative agnosia
ii) apperceptive agnosia
a) ventral stream
b)
i) you have trouble linking obj to memory
ii) you have trouble copying the structure of obj
This is an image demonstrating someone with which of the following kinds of visual agnosia?
a) associative agnosia
b) apperceptive agnosia
b
This is an image demonstrating someone with which of the following kinds of visual agnosia?
a) associative agnosia
b) apperceptive agnosia
a
Which cortex plays a major role in face recognition?
IT - inferior temporal cortex
Describe the Thatcher illusion?
ability for use to recognize a face even when its inverted
T of F - the dorsal stream is evolutionarily older than the ventral stream
T
Describe the purpose of the dorsal stream.
it transforms visual info for the purpose of action or to perform a certain behavior
Match the following
a) Dorsal stream
b) Ventral stream
1. unconscious
2. conscious
a) 1
b) 2
They say that the dorsal stream acts below the lvl of consciousness. What is an experiment that proves this?
Someone is shown two disks that are identical but they perceive them as different is size. Despite this when they go to pick it up they still adjust their hands properly to the actual size not the perceived one.
