plasticity and functional recovery

• what is plasticity


  our brain has the ability to change thought out life, infancy synaptic connections grow rapid (15000 per neuron at 2-3)

  as we age unused connections deleted (synaptic pruning)
• Research into plasticity

  · Maguire et al: brains of London taxi drivers compared to control group.

  . had to learn all roads of london (the knowledge)

  · significantly more grey matter in the posterior hippocampus in the taxi drivers. (associated with the development of spatial and navigational skills)
• how was maguires study controlled

  taxi: male, right handed, 1+ year driving, health

  compared: age, health, gender, no prior driving
• evaluation of maguires study

  ❌small sample

  ❌cross sectional

  ❌how do we know being a taxi driver cause grey matter and not that because of grey matter they wanted to be a taxi driver

  - because positive correlation between time driving and grey matter
• what is draganski et al study

  images of the brain of medical students 3months before and 3 after exams

  -learning induced changes seen in posterior hippocampus and parietal cortex
• negative evaluation of plasticity

  -negative consequences: medina et al: prolonged drug use leads to poorer cognitive functions and increased risk of dementia.

  60-80% phantom limb syndrome which is painful
• positive evaluation of plasticity

  -life long: bezzola et al: 40hours of golf training produced training in neural representations of movement in ages 40-60- increased motor cortex activity so more efficient neural representations.
• what is 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(s) to other, undamaged area(s).
• functional recovery after brain trauma

  unaffected areas of the brain are able to compensate for damages areas.

  -healthy brain areas take over functions of the damaged, destroyed or missing.
• What happens in the brain during recovery?

  The brain rewires and reorganise itself by forming new synaptic connections close to the area damage.

  Secondary neural pathways that wouldn't typically be used to execute functions are activated to enabled.

  axonal sprouting- growth of new ending which connect with undamaged nerve endings

  denervation supersensitivy: axons that do similar jobs go to a higher level to compensate

  recruitment of homologous:
• strength of functional recovery


  Real world application

  - Contributed to the field of neuro rehabilitation

  - Understanding axonal growth is possible, encourages new therapies to be tried

  - E.g. constraint induced movement therapy used with stroke patients where they practice using affected part of the body, while the unaffected arm is restraint
• Limitation of functional recovery


  cognitive reserve

  - Level of education may influence recovery rate

  - schneider et al: more time people with brain injury spent in education, greater chance of disability free recovery (40% who achieved DFR had more than 16 years in education compared to 10% who had less than 12 years)