Plasticity and functional recovery of the brain after trauma

• Plasticity

  brain's tendency to change and adapt as a result of experience and new learning - growth of new connections
• Plasticity- infancy

  Infancy - The brain experiences rapid growth in the number of synaptic connections it has ( twice as many than an adult )
• plasticity - synaptic pruning

  • as we age rarely used connections are deleted and frequently used connections are strengthened
  • lifelong plasticity where new neural connections are formed in response to new demands on the brain
• plasticity research - Maguire

  studied the brains of London taxi drivers

  • significantly more volume of grey matter in the posterior hippocampus than in a matched control group
  • associated with development of spatial and navigational skills in humans and other animals
  • london cab drivers -> complex test called 'the Knowledge which assess their recall of routes
  • this alters the structure of the drivers brains
  • longer the taxi driver had this job the more pronounced the structural difference - positive correlation
• plasticity research - Draganski

  • imaged the brains of medical students 3 months before and after their final exams
  • learning-induced changes were seen to have occurred in the posterior hippocampus and the parietal cortex
• plasticity AO3 - negative behavioural consequences

  • brain's adaptions to prolonged drug use leads to poorer cognitive functioning in later life and increased risk of dementia
  • 60-80% of amputees -> phantom limb syndrome (experience sensations in missing limb - unpleasant) this is due to cortical reorganisation in somatosensory cortex
  • not beneficial
• plasticity AO3 - age and plasticity

  • life-long ability
  • Bezzola - 40 hours of golf training produced changes in neural representations of movement in ppts aged 40-60
  • used fMRI - observed increased motor cortex activity in the novice golfers compared to a control group
  • more efficient neural representations after training
• functional recovery

  A form of plasticity. Following damage through trauma the brain's ability to redistribute or transfer functions usually performed by a damaged area to other undamaged area
• functional recovery after brain trauma:

  Healthy brain areas take over functions of those areas that are damaged, destroyed or missing

  process occurs quickly after trauma (spontaneous recovery) and then slows down after weeks

  • individual may require rehabilitative therapy
• functional recovery - brain during recovery

  • brain rewires and reorganises itself by forming new synaptic connections close to the area of damage
  • secondary neural pathways are activated to enable functioning to continue
• functional recovery - 3 structural changes in the brain

  • axonal sprouting
  • denervation supersensitivity
  • recruitment of homologous areas
• functional recovery - axonal sprouting

  • the growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways
• functional recovery - denervation supersensitivity

  • occurs when axons that do a similar job become aroused to a higher level to compensate for the ones that are lost
  • can have negative consequences of oversensitivity to messages such as pain
• functional recovery - recruitment of homologous areas

  • on the opposite side of the brain
  • specific tasks can still be performed
  • after time, functionality may shift back to the other side
• functional recovery AO3 -real-world application

  • contributed to the field of neurorehabilitation - understanding axonal growth encourages new therapies to be tried
  • constraint-induced movement therapy is used with stroke patients whereby they repeatedly practice using the affected part of their body
  • helps medical professionals
• functional recovery AO3 - cognitive reserve

  • level of education may influence recovery rates
  • schnieder - more time people with brain injury spend time in education the greater their chances of disability-free recovery
  • 40% who had achieved DFR had more than 16 years of education compared to 10% who had less than 12 years