Brain Plasticity and Functional Recovery

• Brain plasticity is the ability of the brain to modify its connection or re-wire itself. This happens when we learn or experience something. Without this ability the brain would be unable to develop from infancy to adulthood or recover from brain injury. Greater plasticity = more connections as time moves on.
• At birth each infant neuron in the celebral cortex has about 2,500 synapses. Reaching approximately 15,000 by the age of 2-3 years old (double the amount of an adult). Later, synaptic pruning occurs and rarely used connections are deleted and frequently used connections are strengthened.
• Real-life examples

  Playing video games: improves spatial awareness / reduces sensitivity to violence.

  Drug use: changes reward pathways / desensitises receptors to neurotransmitters.

  Driving taxis: increases grey matter (cell bodies) in hippocampus. - 'All London' license requires you to have detailed knowledge of 320 routes covering 25,000 streets.
• Maguire

  66 males - 16 right handed taxi drivers / 50 right handed who did not drive taxis.

  An MRI was completed on all pps which produced a detailed image of the brain. The amount of grey matter in taxi drivers was measured and compared to the control group. They found significantly more grey matter in the hippocampus of taxi drivers than the control group. The no of years they had been a taxi driver correlated with the amount of grey matter. This indicates that the plasticity of the brain can be affected by experiences such as taxi driving.
• Maguire Evaluation

  Use of scientific measurements - no demand characteristics or social desirability - increases internal validity / huge RWA as understanding plasticity can help development of treatment for brain trauma patients / the taxi drivers weren't measured before 'the knowledge' meaning we cannot establish cause and effect / only male sample (beta bias) - cant be generalised.
• Functional Recovery

  Often, after brain trauma, patients do not fully recover all their functions. However, due to the brain's plasticity it is possible for the brain to recover some of the functions it has lost.

  Functional recovery = the brain reassuming its normal function after it has been damaged.
• • The plasticity of the brain allows it to cope better with 'indirect' effects of brain damage (blood vessels reform in order to heal the brain).
  • The brain recovers by transferring functions to undamaged areas.
  • Recovery is helped through a process of neural regeneration (undamaged axons sprout new nerve endings to reconnect with neurons).
  • When the number of dendrites connected to a neuron becomes reduced, the ones that remain become sensitive to neurotransmitters to allow communication to continue.
• Gender differences in functional recovery: studies have found that women recover slower then men after a stroke - Kim et al found that in sample of over 1000 stroke patients the women were much more likely to have poor functional outcomes a year after their stroke compared to the men. However, Ratcliff found that recovery language ability in women was quicker than in men.

  Age differences in functional recovery: When the brain is still maturing, recovering from trauma is more likely. Neural regeneration is much more limited in the adult brain (still possible with use of stem cell injections).
• Therapy: Functional recovery can be enhanced with therapy. The more sensory and motor stimulation a person recieves, the more likely they will recover from brain trauma.

  Educational differences in functional recovery: Schnieder et al found that patients who were educated beyond high school were much more likely to recover than those who weren't. This means that education increases the brain's resilience to brain damage and increases the likelihood of functional recovery.