plasticity and functional recovery

Question 1

What is brain plasticity

Answer 1

The brain’s tendency to change & adapt as a result of experience & new learning.

Question 2

Plasticity Research: Maguire et al

Answer 2

London Taxi Drivers:
- Studied brains of London taxi drivers.
- Found significantly more volume of grey matter in posterior hippocampus than in control group.
- Hippocampus; associated with development of spatial & navigational skills.
- Result of learning complex routes is to alter structure of taxi drivers’ brains.
- The longer they had been in the job; the more pronounced was the structural difference (positive correlation).

Question 3

Functional Recovery

Answer 3

A form of plasticity:
following damage through trauma, the brain’s ability to redistribute/transfer functions usually performed by a damaged area to another undamaged area.

Question 4

What happens in the brain during recovery?

Answer 4

• Brain is able to rewire & reorganise itself by forming new synaptic connections close to damaged area.
• Secondary neural pathways not typically used for certain functions are activated to enable continued functioning.

Question 5

Structural changes in the brain

Answer 5

• Axonal sprouting.
• Reformation of blood vessels.
• Recruitment of similar areas on opposite side of brain.

Question 6

Axonal Sprouting

Answer 6

The growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways.

Question 7

Recruitment of similar areas

Answer 7

Recruitment of similar areas on the opposite side of the brain to perform specific tasks.
E.G: if Broca’s area was damaged on the left side of the brain - the right sided equivalent would carry out its functions.
- After time, functionality may shift back to left side.

Question 8

Practical Application

Answer 8

Understanding processes of plasticity has contributed to neurorehabilitation:
- Following illness/injury to the brain- spontaneous recovery slows down after weeks.
- Forms of physical therapy may be required to maintain improvements in functioning.
- E.G: movement therapy & electrical stimulation of brain (to counter the deficits in motor/cognitive functioning).
= Although brain may be able to “fix itself” - this process requires further intervention to be completely successful.

Question 9

Negative Plasticity

Answer 9

Brain’s ability to rewire itself can sometimes have maladaptive behavioural consequences:
- Prolonged drug use has been shown to result in poorer cognitive functioning & increased risk of later dementia.
- 60-80% of amputees have been known to develop phantom-limb syndrome.
= These sensations are usually unpleasant, painful & thought to be due to cortical reorganisation in somatosensory cortex (occurs as result of limb loss).

Question 10

Reduces With Age

Answer 10

Functional plasticity tends to reduce with age:
- Brain has greater tendency for reorganisation in childhood & constantly adapts to new experiences & learning.
Bezzola et al:
- Demonstrated how 40 hours of golf training produced changes in neural representation of movement in ages 40-60.
- Using fMRI; observed reduced motor cortex activity in novice golfers compared to control group (suggests more efficient neural representations after training).
= Neural plasticity does continue throughout the lifespan.