plasticity and functional recovery

• brain plasticity - the brain's tendency and ability to change and adapt both functionally and physically as a result of new learning
• functional recovery - a form of plasticity that occurs after damage through trauma, the brain's ability to redistribute or transfer functions usually performed by a damaged region to another area of the brain
• what physically happens in the brain during development?

  • during the first 2-3 years the brain has a rapid growth in the number of synaptic connections reaching 15000 (twice as many as the normal adult brain)
  • synaptic pruning - rarely used connections are deleted as we age and frequently used connections are strengthened
  • synaptic pruning happens throughout life as a result of learning and experience
• functional recovery after trauma

  • after physical injury or trauma unaffected areas of the brain can adapt and compensate for the damaged areas
  • often happens quickly after trauma and then slows down
  • brain rewires and forms new neural connections close to the area of damage
• how does the brain rewire?

  • neural sprouting - the growth of new axon endings which connect to other nerve cells to create new pathways
  • reformation of blood vessels
  • recruitment of homologous areas on the opposite side of the brain
• evidence for functional recovery

  • jodi - had a right hemispherectomy due to rapid onset seizures starting in the right hemisphere and her left side took control of the left side of her body and the functions of the right hemisphere
  • eb - had a left hemispherectomy and initially lost all language abilities but relearned all skills and had no deficits except surface-level dyslexia
• evaluation

  
 + practical applications

  + neurorehabilitation - techniques such as electrical stimulation and speech/movement therapy help the brain rewire

  - age and plasticity - functional plasticity decreases with age so not everyone would have as much success as jodi or eb

  + supporting evidence

  - cognitive reserve - ability to recover from trauma is linked to educational achievement so not everyone is equally able to recover

  - not all plasticity is a good thing eg. phantom limb syndrome

  - hard to generalise from case studies
• research support for plasticity

  • maguire et al - london taxi drivers have a larger hippocampus than non-taxi driver controls
  • bezzola et al - studied novice golfers between age 40-60 and gave them 40 hours of training and found their motor cortex shrunk as the action became automatic
  • lazar et al - used mri scans and found meditators had a thicker cerebral cortex in areas related to attention and sensory processing
  • other studies found changes in the left hippocampus -- linked to learning -- and the cingulate gyrus -- linked to self regulation