Development Of Visual Cortex

Question 1

What is the visual cortex

Answer 1

The area of cerebral cortex at back of brain that receives and processes visual info

Question 2

What are ocular dominance columns

Answer 2

Neurones in visual cortex grouped together in columns, right ocular dominance column receives info from right eye

Question 3

How are ocular dominance columns arranged

Answer 3

Same size and arranged in alternating patterns across visual cortex of L and R

Question 4

What did Huber and Wiesel find

Answer 4

Left ocular dominance columns stimulated when animal uses it’s left eye and right ocular dominance columns stimulated when used right eye

Question 5

Outline Huber and Wiesel’s study on kittens and what does this show

Answer 5

-stitched shut one eye of each kitten so only able to see out of other eye for several months before eyes were unstitched
-found eye that had been stitched up was blind and ocular dominance columns for stitched up eye were a lot smaller than normal and columns for open eye bigger than normal, had expanded to take over the other columns that weren’t being stimulated meaning neurones in visual cortex switched dominance
-shows visual cortex only develops into normal left and right ocular dominance columns if both eyes visually stimulated in very early stages of life

Question 6

Study on adult cats

Answer 6

Found that stitched up eye hadn’t gone blind, cats fully recovered their vision and their ocular dominance columns remained same

Question 7

What is critical period

Answer 7

Period in early development when nervous system must obtain specific experiences to develop properly so synapses strengthened, beginning at around 4 weeks

Question 8

Expand on cataract investigation in humans

Answer 8

-cataracts make lens cloudy causing blurry vision
-if baby had cataract must remove within first few months of life otherwise visual system won’t develop properly and vision damaged for life
-if adult has cataract when removed normal vision comes back straight away as visual system already developed

Question 9

What happens during critical period in visual cortex

Answer 9

-ocular dominance columns develop in visual cortex, neurones form synapses with these columns, if these neurones stimulated the connections between them are strengthened
-stimulation during critical period needed to form effective connections in VC
-if neurones not stimulated this weakens connections and synapses destroyed