Brain Plasticity

• methods for functional recovery

  • synapse strengthening
  • rewiring / axonal sprouting
  • neuronal unmasking
  • denervation supersensitivity
  • recruitment of homologous areas

  srand - syn.. rec.... axonal..... neuronal.... denerv....
• synapse strengthening is when either

  • the number of neurotransmitters released increases so that more charged particles are able to go into the post synaptic neuron
  • the number of receptors available increases, which has the same effect

  synapses in nearby neurons will strengthen to take over the function of the damaged region
• rewiring or axonal sprouting is when axons from neurons that used to communicate with the damaged region grow out and form new neuronal pathways to adjacent regions in order to compensate for the loss of the function
• neuronal unmasking

  • over time, synapses can become inactive due to lack of electrical activity within the pre-synaptic terminal. they become silent synapses where even if an electrical impulse did occur, no neurotransmitters would be released.
  • BUT if the pre synaptic terminal becomes excessively active then eventually the silent synapse can become active again, meaning neurons will start to communicate again
• recruitment of homologous areas is when other parts of the brain take over the functions of the damaged area. these areas have similar structure and function as the original part of the brain but aren't normally involved in those processes. they are recruited because they are close to the damaged area and therefore have access to the relevant sensory information

  these areas may just be on the other hemisphere of the brain but in the same location
• denervation supersensitivity is when axons that do a similar job become arouse to a higher level in order to compensate for those lost

  HOWEVER it can have negative consequences, such as causing oversensitivity to messages such as pain
• Maguire - Taxi driver study

  quasi experiment

  compared the amount of grey matter in the hippocampi of london taxi drivers and non-taxi drivers.

  found that taxi drivers had larger amounts of grey matter, which increased with the length of time that they had been taxi driving

  this supports the idea that the brain changes based on new experiences and therefore supports brain plasticity
• Maguire's study

  as it was a quasi experiment, participant variables were not able to be manipulated

  so the IV was not manipulated

  and so its difficult to establish a cause and effect relationship between variables
• Kuhn's video game study

  laboratory study

  asked participants to play mario every day for 30 minutes for 2 months

  while the control participants were instructed to not do this

  Kuhn imaged their brains and found that the experimental group had increased brain volume in parts of the brain involved in fine movement control, spatial skills and planning

  suggests that learning is accompanied by plastic changes in the brain
• Elbert et al did a study on brain plasticity in children and adults

  found that children's brains are more plastic than adults brains, meaning that there is an extent to brain plasticity
• One limitation of brain plasticity is that it may have negative behavioural consequences. Ramachandran and Hirstein found that 60-80% of amputees experience phantom limb syndrome

  which is thought to be due to cortical reorganisation in the somatosensory cortex that occurs in response to limb loss

  this suggests that the brain's ability to adapt to damage is not always beneficial