Blakemore And Cooper

Question 1

Define visual cortex.

Answer 1

The part of the brain that receives and processes sensory nerve impulses from the eyes.

Question 2

Define startle response.

Answer 2

The ‘backing off’ reaction of a cat when an object is moved quickly towards their face.

Question 3

Define visual placing.

Answer 3

When the cat puts its feet out to meet the edge of a surface.

Question 4

Define brain plasticity.

Answer 4

The idea that your brain adapts and changes according to what you do in your life and the demands placed on it by forming new neural connections.

Question 5

What was the background to Blakemore and Cooper’s study?

Answer 5

• Hirsch and Spinelli investigated the visual cortex in kittens. They wore goggles so they could see only horizontal stripes in one eye and vertical stripes in the other. When the goggles were removed, the kittens showed visual deficits and their visual neurones had adapted to the environment they had seen in each eye.
• Blakemore and Cooper wanted to build on this research by using multiple cats (one only seeing vertical stripes and one only seeing horizontal stripes) rather than having the same cat see both.

Question 6

What was the aim of Blakemore and Cooper’s study?

Answer 6

• To investigate the effects of being raised in a restricted environment in kittens:
  
  • Investigate the effects of this environment on their behaviour.
  • Investigate the neurophysiological effects on neurons in the kittens’ visual cortex (to see if they have brain plasticity).

Question 7

What was the sample in Blakemore and Cooper’s study?

Answer 7

• Kittens
• Studied from birth to roughly 1 year old

Question 8

Why were kittens used in Blakemore and Cooper’s study?

Answer 8

• Unethical to use human infants
• Visual cortex is in a similar place to humans
• Eyes are binocular and see in colour

Question 9

What controls were put in place in Blakemore and Cooper’s study?

Answer 9

• Kittens wore a collar so they could not see their body (130° width of vision).
• Kept in a completely dark room when not in the cylinder and for the first 2 weeks so their only visual information was the stripes.
• Same amount of time each day (5 hours) in the cylinder.
• Both tested after 5 months in the same environment.

Question 10

What was the procedure in Blakemore and Cooper’s study?

Answer 10

• Newborn kittens were raised in a completely dark room for 2 weeks.
• At 2 weeks, the kitten was placed inside a cylinder for 5 hours a day (then returned to the dark room for the rest of the time).
• The kittens were only able to see either horizontal or vertical lines until they reached 5 months old.
• After 5 months (this was thought to be the critical period for brain development) they were put in a well-lit room with furniture (including tables and chairs) and their behaviour was observed over several weeks.

Question 11

What were the two types of results (and type of data) found in Blakemore and Cooper’s study?

Answer 11

• Behavioural (qualitative)
• Neurophysiological (quantitative)

Question 12

Regarding behavioural results, which visual deficits did the cats show when first exposed to the well lit room in Blakemore and Cooper’s study?

Answer 12

• No visual placing when carried towards a table.
• No startle response when an object or hand was thrust towards them.
• They navigated the room around by touch.
• They were generally clumsy.

Question 13

Regarding behavioural results, which visual deficits disappeared after 10 hours of being exposed to the well lit room in Blakemore and Cooper’s study?

Answer 13

• They showed startle response.
• They showed visual placing.
• They would jump with ease from a chair to the floor.

Question 14

Regarding behavioural results, which visual deficits remained in the cats in Blakemore and Cooper’s study?

Answer 14

• They always followed moving objects with very clumsy, jerky head movements.
• They often tried to touch things moving on the other side of the room, well beyond their reach.
• They continued to bump into objects when scurrying around the room.

Question 15

How was the kittens’ blindness to the other orientation tested in Blakemore and Cooper’s study?

Answer 15

• When a Perspex sheet containing black and white stripes was held in front of them in the same orientations as their cylinder they showed a startle response but showed no reaction when it was presented in the opposite orientation.
• When a rod was shaken in front of them, the kittens would only try to grab it when held in the same orientation.

Question 16

What was the neuropsysiological part of the procedure in Blakemore and Cooper’s study?

Answer 16

• The two cats were anaesthetised and paralysed with their eyes opened.
• Electrodes were inserted into the primary visual cortex to take electrical readings from individual neurons.
• Visual neuron activity was recorded to show the optimal orientation for each neuron when shown bright slits of light.

Question 17

What neurophysiological results were found in Blakemore and Cooper’s study?

Answer 17

• The visual neurons within the primary visual cortex had aligned themselves to match the environment the kitten was brought up in.
• There were little to no neurons aligned to the opposite orientation as the cats had no need for neurones in the other direction and therefore these moved elsewhere.

Question 18

What conclusions were made from Blakemore and Cooper’s study?

Answer 18

• The visual environment has changed the kittens brains - the neurons of their brains had resided themselves based on the environment they were exposed to (so the horizontally raised cat could no longer see vertical lines and vice versa).
• This is evidence of brain plasticity.