HL Animal: Brain and Behaviour

Question 1

Aim of Merzenich

Answer 1

to investigate cortical representation and neuroplasticity

Question 2

Method of Merzenich

Answer 2

Researchers studied the cortical representation of the hand in 8 adult owl monkeys.

1. Sensory inputs from all the hand digits (fingers) were mapped in the cortex. (by inserting electrodes in the cortical area known to be responsible for sensation from the hand, noted with finger responded to which electrode)
   2.Monkeys were anesthetized before the procedure.
   3.The third digit (middle finger) on the monkey’s hand was amputated.
   4.62 days later a remapping was done to see how the cortical area responsible for sensitivity from the hand changed after the amputation.

Question 3

Findings of Merzenich

Answer 3

From first mapping
* showed there were 5 distinct areas in the brain, ** each responsible for one finger**, and adjacent fingers were represented in adjacent areas in the cortex

From second mapping
* found that the adjacent areas (those responsible for sensitivity from digits 2 and 4) spread and occupied parts of the now unused area
* The areas responsible for digits 2 and 4 became larger while the areas resonsible for digits 1 and 5 stayed the same

Question 4

Conclusion of Merzenich

Answer 4

It was concluded that cortical remapping of sensory inputs from the hand occurs within 62 days in owl monkeys

Question 5

Aim of Rosenzweig, bennet & diamond

Answer 5

to investigate whether environmental factors such as a rich or impoverished environment would affect the development of neurons in the cerebral cortex

Question 6

Method of Rosenzweig, bennet & diamond

Answer 6

• Rats from a common litter were used
• each randomly allocated to one of three environments
• control: 3 rats were in a cage
• impoverished condition: each rat was in a different cage that lacked toys and the maze which could be found in the enriched environment
• enriched condition: placed 10-12 rats in a cage containing stimuli objects to explore and play with
• All groups had free and adequate access to food and water
• rats spent 30-60 days in their respective environments before they were killed to study the changes in the brain’s anatomy

Question 7

Findings of Rosenzweig, bennet & diamond

Answer 7

• Brain anatomy was different in the enriched and impoverished condition
  EC:
• Increased thickness and higher weights of cortex
• developed significantly greater activity in the neurons in the cerebral cortex (which is associated with a higher transmission of acetylcholine, a neurotransmitter helping with learning and memory)
• Follow-up of this research indicated that just 2 hours a day in an enriched environment produced the same plastic changes in the brain as in rats that had been constantly in the EC condition. This shows that the brain can change and adapt to new situations.

Question 8

Conclusion of Rosenzweig, bennet & diamond

Answer 8

Brain plasticity is assumed to have same patterns in both animals and humans, so from this we can apply what we know about an unstimulating environment effects on rats, to humans.
(also supported by luby et al - negative experiences)

Question 9

Ayumu the chimpanzee

Answer 9

• intelligence test for chimps
• Working Memory: brains ability to temporarily store and use info
• Info 1-9 randomly scattered on touch screen
• screen stays and long as needed to memorise
• as one is touched the other numbers dissapear
• chimp needs to remember and choose
• Need to recall in ascending order

Human
* takes ages to remember
* only successful in 1/30 attempts

Chimp
* super quick
* correctly remembers almost 90% of the time