Brain plasticity and functional recovery

• Plasticity is the ability of the brain to change and adapt to new changes in the environment.
• Reasons for plasticity:

  • Learning new skills,
  • Developmental changes,
  • Direct trauma to the brain,
  • Indirect effects of damage (brain swelling or bleeding from a stroke).
• Functional recovery is the ability of the brain to regain functions that were performed in the before damage that are now performed in the undamaged areas of the brain. This is also known as functional reorganisation.
• Synaptic pruning is when the synapses that are used frequently become stronger over time, whereas unused synaptic connections are lost. This makes the brain more efficient in communicating.
• Axon sprouting it the growth of new axons on existing neurones to connect to adjacent neurones. Neural recognition is the growth of new neuronal cells.
• Denervation sensitivity is the increase in sensitivity to compensate for the loss of axons in a pathway. This can result in side effects such as pain.
• Maguire (2000) studied the brains of 16 male taxi drivers through MRI scans and these were compared to match the scans of non taxi driver controls. Findings showed the posterior hippocampi in London taxi drivers were larger than the controls. This suggests that the physical structure of the brain is able to reconfigure itself to better adapt psychological demands, in this case to improve memory.
• Danelli (2013) conducted a case study of a 14 year old (EB). At the age of 2 and a half, EB had a hemispherectomy on the left side of his brain to remove a tumour. This removed the Broca's and Wernicke's area, resulting in global aphasia. However after 2 years of recovery, EB recovered his language ability on his right hemisphere, although still suffering from some dyslexia like symptoms. This suggests the brain has the ability to adapt even after significant damage, especially in early life.
• Strengths of brain plasticity:

  • Practical applications - Useful in rehabilitative therapy which has helped people return to normal lives and productive work, benefitting the economy.
• Limitations of brain plasticity:

  • Negative behavioural consequences - Ramachandran and Hirstein (1998) investigated how 60-80% of amputees develop phantom limb syndrome (continued sensations of the missing limb as if it was there) thought to be due to the reorganisation of the somatosensory cortex, suggesting structural and physical processes involved in functional recovery may not always be beneficial.