plasticity & functional recovery

• Plasticity describes the brain’s tendency to change and adapt (functionally and physically) as a result of experience and new learning
• Functional recovery is a form of plasticity. Following damage from trauma, the brain’s ability to redistribute or transfer functions usually performed by a damaged area, to another undamaged area
• Maguire (2000) studied the brains of London taxi drivers and found significantly more grey matter (the darker tissue of the brain and spinal cord, consisting mainly of nerve cell bodies and branching dendrites) in the posterior hippocampus than the matched control group
• the hippocampus is an area of the brain involved in the development of spatial and navigational skills in humans
• Mechelli et al (2004) also found a larger parietal cortex (important for language learning) in the brains of people who were bilingual compared to matched monolingual controls
• Draganski et al (2006) imaged the brains of medical students 3 months before and after their exams. Learning induced changes were seen to have occurred in the posterior hippocampus and the parietal cortex presumably as a result of the exam
• There are 3 main anatomical ways the body can replace axon function in the brain after trauma:

  • increased brain stimulation
  • axon sprouting
  • reformation of blood vessels
• Increased brain stimulation: homologous (similar) areas on the opposite side of the brain perform specific tasks originally performed by the damaged area
• Axon sprouting: a sprouting neuron can produce extra connections (nerve endings) replacing lost ones and forming new neural pathways. It helps to replace function if the new neurons do the same job as the damaged ones
• understanding of brain plasticity has advanced the rehabilitation processes and techniques available to patients with brain injury
• The brain ability to revive itself can sometimes have maladaptive behavioural consequences. 60-80% of amputees experience phantom-limb syndrome. These sensations are usually unpleasant and thought to be due to cortical reorganisation of the somatosensory cortex
• Bezzola et al shows that neural plasticity continues throughout the lifespan and is not restricted to one specific age group
• Hubel and Wiesel sewed shut the eye of a kitten and analysed the brain’s response to this. It found that the area of the visual cortex connected to the shut eye remained active and processed information from the open eye
• the early research into plasticity was conducted through animal studies, which means there are problems with generalisation
• Bezzola et al (2012) demonstrated how 40 hours of golf training produced changes in the neural representation of movement in participants aged 40-60. Using fMRI, the researchers observed reduced motor cortex activity in the novice golfers compared to a control group suggesting more efficient neural representations after training