Plasticity and functional recovery

Question 1

what is plasticity?

Answer 1

• This describes the brain’s tendency to change and adapt as a result of experiences and new learning. This generally involves the growth of new connections.
  
  • During infancy the brain experiences a rapid growth in number of synaptic connections it has, peaking at 2-3 years old. This is twice as many as the adult brain.
  • As we age rarely-used connections are deleted and frequently-used connections are strengthened, this is a process known as synaptic pruning.
  • Synaptic pruning enables life-long plasticity where new neural connections are formed in response to new demands of the brain.

Question 2

what was Maguire’s research?

Answer 2

• Maguire studied the brains of London taxi drivers and found significant more volume of grey matter in their posterior hippocampus than in the matched control group.
  
  • This part of the brain is associated with the development of spatial and navigational skills. London taxi drivers have to take ‘The Knowledge’ test which assesses their recall of the city streets and possible routes.
  • Maguire et al found that this learning experience alters the structure of the taxi driver’s brains. Also found a positive correlation with the length of time in the job and how much more pronounced the structural difference was.

Question 3

what was Draganski’s research?

Answer 3

Draganski imaged the brains of medical students 3 months before and after their final exams.
Learning-induced changes were seen to have occurred in the posterior hippocampus and parietal cortex presumably as a result of learning.

Question 4

what is functional recovery?

Answer 4

• Following physical injury, unaffected areas of the brain are often able to adapt and compensate for those areas that are damaged.
  
  • The functional recovery that may occur in the brain after trauma is an example of neural plasticity.
  • Healthy brain areas may take over the functions of those areas that are damaged, destroyed or even missing.
  • Neuroscientists suggest that this process can occur quickly after trauma and then slow down after several weeks or months.
  • Individual may require rehab therapy to further their recovery.

Question 5

what structural changes occur in functional recovery?

Answer 5

• Axonal sprouting- the growth of new nerve endings which connect with other undamaged nerve cells to form new neural pathways.
  
  • Denervation supersensitivity- occurs when axons that do a similar job become aroused to a higher level to compensate for the ones that are lost.
  • Recruitment of homologous areas- Means that specific tasks can still be preformed. If left-side damaged right-side equivalent would take on its role.

Question 6

what is a limitation of Plasticity?

Answer 6

• One limitation of plasticity is that it may have negative behavioural consequences.
  
  • Evidence has shown that the brain’s adaptation to prolonged drug use leads to poorer cognitive functions later on in life as well as increased dementia (Medina et al)
  • 60-80% of amputees also develop phantom leg syndrome, these sensations are usually unpleasant and painful.
  • This suggests that the brain’s ability to adapt to damage is not always beneficial.

Question 7

what is a strength of plasticity?

Answer 7

• One strength is that brain plasticity may be a life-long ability
  
  • Although plasticity reduces with age, Bezzola et al demonstrated how 40 hours of golf training produced changes in the neural representations of movement in participants ages 40-60.
  • Using fMRI researchers also observed increased motor cortex activity in the novice golfers compared to a control group, suggesting more efficient neural representations after training.
  • This shows that neural plasticity can continue throughout the lifespan.

Question 8

what is a strength of functional recovery?

Answer 8

• Understanding the processes involved in plasticity has contributed to the field of neurorehabilitation.
  
  • Simply understanding that axonal growth is possible encourages new therapies to be tried.
  • This shows that research into functional recovery is useful as it helps medical professionals know when interventions need to be made.

Question 9

what is a limitation of functional recovery?

Answer 9

• One limitation of functional recovery is that level of education may influence recovery rates.
  
  • Schneider et al revealed that the more time people with a brain injury spent in education, the grater there chances of a disability free recovery.
  • 40% of those who had achieved a DFR had more than 16 years of education compared to about 10% of those who had less than 12 years education.
  • This would imply that people with brain damage who have insufficient DFR are less likely to achieve full recovery.