Plasticity + functional recovery

• Brain plasticity

  Brain's tendency to change and adapt due to experience and learning. Makes new connections.

  E.g. infancy has rapid growth of synaptic connections at 15,000 per neuron.

  Synaptic pruning occurs which is when rarely-used connections are deleted and frequentluy-used ones are strengthened
• Research into plasticity - Taxi drivers

  Maguire et al

  Studied brains of London taxi drivers.

  Significantly more volume of grey matter in the hippocampus than control group. This part of the brain is associated with spatial and navigation skills.
• Strength - age + plasticity

  Life long ability

  Bezzola et al.

  40hrs of golf training produced changes in neural representations of movement in participants aged 40-60.

  fMRI showed increased motor cortex activity in novice golfers compared to control group.
• Limitation - negative plasticity

  May have negative behavioural consequences

  Brain's adaptation to prolonged drug use leads to poorer cognitive functioning later in life and increased risk of dementia.

  60-80% of amputees experience phantom limb syndrome.

  Due to cortical reorganisation in the somatosensory cortex
• Functional recovery

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

  Occurs quickly after trauma but then slows down after several weeks/months
• Axonal sprouting

  Growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways.
• Denervation supersensitivity

  Axons that do a similar job become aroused to a higher level to compensate for the ones that are lost.

  Can have negative consequence to oversensitivity to messages e.g. pain
• Recruitment of homologous areas

  Similar areas on the other side of the brain perform the tasks.
• Strength - real world application of functional recovery

  Understanding processes has contributed to field of neurorehabilitation.

  Understanding axonal growth encourages new therapies to be tried. E.g. constraint-induced movement therapy used by stroke patients.
• Limitation - level of education on functional recovery

  Schneider et al

  More time people with a brain injury had spent in education the greater chance of disability-free recovery.

  40% who achieved DFR had more than 16yrs education.

  10% had less than 12 years of education.