plasticity and functional recovery

• plasticity is also known as neuroplasticity
• plasticity definition

  the brains ability to change and adapt as a result of change and new learning
• what is bridging, why does it occur and when does it occur?

  new connections being formed due to new change/stimuli

  occurs during infancy and peaks around 2-3
• what is pruning, why does it occur and when does it occur?

  connections eliminated due to lack of use

  helps the brain work more effectively and enables life long plasticity as the brain is more refined and efficient in adulthood

  happens in new borns and adolescents
• evaluating plasticity

  :-) evidence to support from maguire et al

  mri scans - positive correlation between size of posterior hippocampus and time individual spent as a taxi driver compred to control

  :-( correlation doesn't equal causation

  :-) further evidence from kuhn

  :-( negative behavioural consequences for amputees with phantom limb syndrome, brains ability to adapt is limited
• evaluating plasticity - kuhn

  kuhn asked participants to play 30 minutes of mario for a day for over two months, there was significant differences in the brain matter of video gaming participants, particularly in the cortex, hippocampus and cerebellum (coordination and movement)

  suggests brain plasticity is real!

  high mundane realism
• functional recover definition

  unaffected areas of the brain adapting and compensating for the damaged areas
• spontaneous recovery - recovery happens quickly before slowing down, which is where patients may need rehab
• axonal sprouting aka neural regeneration
• axonal sprouting

  growth of new nerve endings which connect to undamaged nerve cells to form new neuronal pathways to the same dendrite

  • creates a route around the broken area to maintain neural connections
  • supported with blood vessels
• recruitment of homologous areas aka neural reorganisation
• recruitment of homologous areas

  when similar areas on the opposite side of the brain perform a specific task, eg if broca's area was damaged the equivalent area in the right hemisphere would carry out it's functions

  • a route around the broken area using opposite sides of the road
• denervation supersensitivity

  when axons that do a similar job to the ones that are damaged become aroused to a higher level to compensate for ones that are lost

  can increase in sensitivity of the post syn

  this can have a negative effect if it's pain
• functional recovery evaluation

  :-) neurorehabilitation. understanding axonal growth encourages new therapies to be trialled to maximise this plasticity, constraint induced movement is successfully used in stroke patients - higher qol

  :-( negative behavioural consequences, phantom limb syndrome, reorganisation kinda sucks

  :-) plasticity continues with age despite the brain reorganising more in childhood, bezzola et al found 4-hrs of golf training 40-60y can increase neural representations of movement