Brain plasticity and functional recovery

Question 1

What is brain plasticity?

Answer 1

This describes the brain’s tendency to change and adapt as a result of experience and new learning. This generally involves the growth of new connections

Question 2

What is synaptic pruning?

Answer 2

The brain has the ability to change throughout a lifetime
During infancy you have the highest number of synaptic connections
As we age, the connections we rarely use are deleted and the most frequent ones are strengthened
This is known as synaptic pruning
During life, new neural connections are formed in response to new demands on the brain

Question 3

Name study 1 in research into plasticity

Answer 3

Maguire et al. study into taxi drivers

Question 4

Name study 2 in research into brain plasticity

Answer 4

Draganski et al. study on medical students

Question 5

What were the findings of the taxi driver study?

Answer 5

Significantly more grey matter in the posterior hippocampus of the taxi drivers than in a matched control group
This area of the brain is associated with the development of spatial and navigational skills

Question 6

Describe the taxi driver study

Answer 6

Taxi drivers have to take a test called “The Knowledge” which assesses their ability to recall city streets and routes
This learning experience appears to alter the structure of their brain
Those that had been doing the job longer had even more grey matter

Question 7

Describe the medical students study

Answer 7

Images of the brain of medical students were taken every 3 months before and after their final exams

Question 8

What were the findings of the medical students study?

Answer 8

Changes were seen in the posterior hippocampus and the parietal cortex as a result of the learning

Question 9

Define functional recovery

Answer 9

A form of plasticity. Following damage through trauma, the brain’s ability to redistribute or transfer functions usually performed by a damaged area to other, undamaged area

Question 10

How does functional recovery work after trauma?

Answer 10

Functional recovery of the brain after trauma is an important example of neural plasticity - healthy brain areas take over functions of areas damaged, destroyed or even missing
Neuroscientists suggest this happens quickly after the trauma occurs - spontaneous recovery
However, it slows down - at this point rehabilitation therapy can take place to improve recovery

Question 11

What happens to the brain during recovery?

Answer 11

The brain rewires and reorganises itself by forming new synaptic connections close to the area of damage
Secondary neural pathways that would not typically be used to carry out certain functions are activated or ‘unmasked’ to enable functioning to continue

Question 12

What are 3 structural changes to the brain?

Answer 12

1. Axonal sprouting - growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways
2. Reformation of blood vessels - recruitment of homologous (similar) areas on the opposite side of the brain to perform specific tasks
3. Denervation supersensitivity - when axons that do a similar job become aroused to a higher level to compensate for the ones that are lost (However, it can have a negative consequence of oversensitivity to messages such as pain)

Question 13

Give 2 strengths of plasticity and functional recovery

Answer 13

1. Real world application - Understanding plasticity has contributed to the field of neurorehabilitation
   Axonal growth encourages new therapies to be tried
   EG: constraint-induced movement therapy is used with a stroke patient
   This helps medical professionals know when interventions need to be made
2. Life long ability - Study 1: Bezzola et al. (2012)
   Findings: 40 hours of golf training produced changes in the neural representations of movement in the participants aged 40-60
   fMRIs observed increased motor cortex acitivity in the golfers compared to a control group
   This shows that neural plasticity can continue throughout the lifespan

Question 14

Give 2 limitations of plasticity and functional recovery

Answer 14

1. Potential negative consequences - 60-80% of amputees develop phantom limb syndrome - they continue to get painful sensations in the missing limb
   These are thought to be due to cortical reorganisation in the somatosensory cortex
   This suggests that the brain’s ability to adapt to damage is not always beneficial
2. More related to cognitive reserve - Educational attainment may influence how well the brain functionally adapts after injury
   Schneider et al. (2014) found the more time brain injury patients had spent in education (indication of cognitive reserve), the greater their chances of a disability-free recovery
   This suggets that cognitive reserve is a crucial factor in determining how well the brain adapts after trauma