Plasticity and Functional Recovery of the Brain

• brain plasticity 


  refers to the brain’s ability to modify its own structure and function as a result of experience and new learning
• functional recovery 


  a form of plasticity. refers to the recovery of abilities and mental processes that have been compromised as a result of brain injury or disease
• synaptic pruning 


  with age rarely used synaptic connections in the brain are deleted and frequently used connections strengthened
• 3 structural changes the brain undergoes to help it recover after trauma

  • axonal sprouting
  • reformation of blood vessels
  • recruitment of homologous (similar) areas on the opposite hemisphere
• number of synaptic connections age 2-3 


  roughly 15000
• Eleanor Maguire et al (2000)

  • studied the brains of London taxi drivers
  • as part of their training London Cabbies must take a complex test called ‘the knowledge’ which assesses their recall of the cities and possible routes
  • Maguire scanned their brains using an MRI and found much more grey matter in the posterior hippocampus than in the matched control group. this part of the brain is associated with the development of spatial and navigational skills in humans and other animals
  • it was also found the longer they had been doing the job the more pronounced was the structural difference
• Davidson et al. (2004)

  • compared 8 practitioners of Tibetan meditation with 10 student volunteers with no previous mediation experience
  • both groups fitted with electrical sensors and asked to meditate for short period
  • there was much greater activation of gamma waves in the monks compared to the students
  • the monks had far more gamma wave activity than the control group even before they started meditating, suggesting that meditation may produce permanent changes in the brain
• functional recovery after trauma 


  following physical injury or other forms of trauma such as infection or the experience of a stroke, unaffected areas are sometimes able to adapt or compensate for damaged areas. the functional recovery that occurs in these cases is an extreme example of neural plasticity. neuro scientists suggest that this can happen quickly after trauma (spontaneous recovery) and then slow down after several weeks or months. therapy may then be needed
• axonal sprouting 


  new nerve endings grow and connect with other undamaged nerve cells to form new neural pathways
• recruitment of homologous areas on the opposite hemisphere


  to do specific tasks. eg if Broca’s area was damaged then the right-sided equivalent would carry out its function. after time, functionality may then shift back to the left. evidence for this= patient J.W.