Plasticity and Functional Recovery

Question 1

What is Plasticity?

Answer 1

• Brain has ability to change throughout life, in infancy brain has rapid growth in number of synaptic connections peaking at 15,000 neurons at 2-3 years of age (Gopnik), twice as many as in adult brain
• as we age rarely used connections are deleted and frequently used are strengthened (synaptic pruning) - which enables lifelong plasticity)

Question 2

Who and what research was done into plasticity?

Answer 2

• Maguire studied london taxi driver brains - much more volume of grey matter in the posterior hippocampus (associated with spatial and navigational skills) than in a matched control group
• completing ‘the knowledge’ alters structure of drivers brains
• loner divers been in job, more pronounced the structural differences were
• Draganski imaged brains of medical studenst 3 months before and after exams: structural differences in the posterior hippocampus and parietal cortex

Question 3

What is functional recovery?

Answer 3

• after brain trauma areas of the brain are able to compensate for the damaged areas, functional recovery is an example of neural plasticity
• can occur quickly (spontaneous recovery) and then slow down after weeks or months meaning the patient may need further rehabilitative treatment

Question 4

What happens to the brain during functional recovery?

Answer 4

• brain rewire/reorganises itself by forming new synaptic connections close to damaged area, secondary neural pathways are ‘unmasked’. Involves structural changes such as:
• Axonal sprouting: growth of new nerve endings that connect with other undamaged nerve cells to form neuronal pathways
• Denervation supersensitivity: when axons that do a similar job become aroused to a higher level to compensate for those lost (can cause oversensitivity to pain)
• Recruitment of homologous areas: similar areas on the other side of brain so specific tasks can still be performed e.g brocas area gets damaged so right side carries out its functions.

Question 5

What is a limitations of Plasticity?

Answer 5

• may have negative consequences, 60-80% of amputees develop phantom limb syndrome - sensations in the missing limb as if it were still there which are usually painful and due to cortical reorganisation in the somatosensory cortex (Ramachandran and Hirstein) brains plasticity may not always be beneficial

Question 6

What is one Strength of Plasticity?

Answer 6

• plasticity reduced with age, however Bezzola demonstrated how 40 hours of golfing produced changes in the neural representations of movement in participants 40-60. increased motor cortex activity according to fMRIs.

Question 7

What is one strength of functional recovery?

Answer 7

• understanding has led to developments in neurorehabilitation, axonal growth is possible encourages new therapies to be tested e.g constraint induced movement therapy for stroke patients

Question 8

What is one limitation of functional recovery?

Answer 8

• level of education may impact recovery rates, schneider revealed more time people spent in higher education greater their chances of a disability free recovery, 40% who received DFR had spent more than 16 years in education compared to 10% in those with less than 12.