The critical period

Question 1

What is the critical period

Answer 1

Length of time after birth in which the connections needed for vision are still developing

Question 2

What can disruptions in the critical period cause

Answer 2

Lifelong visual impairment

Question 3

How can critical period be shown by cataracts

Answer 3

When cataracts are removed from children they are left with impaired vision. But if an old person gets a cataract their vision is not impairs once the cataract is removed

Question 4

Who conducted research into the critical period and when

Answer 4

Hubel and Wiesel in the 1960s

Question 5

What did Hubel and Wiesel find about New-born monkeys raised under darkness

Answer 5

New-born monkeys raised under darkness did not develop normal vision, showing that light was necessary

Question 6

What did Hubel and Wiesel find about New-born monkeys raised under diffuse light with no shapes

Answer 6

They did not develop normal vision showing shapes are necessary

Question 7

What is it called when you cover one eye

Answer 7

Monocular deprivation

Question 8

What did Hubel and Wiesel find about New-born monkeys raised under Monocular deprivation

Answer 8

The monkey became blind in the covered eye, but the photoreceptors in the eye still worked

Question 9

What was the thing causing the blindness in the monocular deprived monkeys

Answer 9

Cells in the visual cortex that were not responding to the light

Question 10

What did Hubel and Wiesel find about New-born monkeys raised with both eyes covered up

Answer 10

The monkey did not end up being blind but had the same visual problems as the monkeys brought up in the dark

Question 11

In the developing monkey describe the synapses for neurones coming from the eyes the eyes

Answer 11

The synapses for the neurones coming from the left and right eye overlap

Question 12

What happens to neurones in the eyes with visual stimulation

Answer 12

The neurones release neurotransmitter which strengthens them

Question 13

What happens to neurones in the eyes without visual stimulation

Answer 13

The neurones don’t release neurotransmitter and are weakened

Question 14

What happens to neurones in the eye with Monocular deprivation

Answer 14

The synapses for the monocular deprived eye break down and the synapses from the other eye become stronger and take over the space in the visual column. This leads to large columns for the normal high and very think columns for the monocular deprived eye

Question 15

What happens to neurones in the eye with both eyes covered

Answer 15

The competition between them is the same and the columns stay the same width