Plasticity and functional recovery

• Plasticity

  During infancy, the brain experiences a rapid growth in synaptic connections, peaking at about 15,000 at age 2 - 3 years. As we age, rarely used connections are deleted and frequently used connections are strengthened which is known as synaptic pruining. It was once thought these changes were limited to childhood. But recent research suggests neural connections can change or be formed at any time, due to learning and experience.
• Plasticity and london taxi drivers

  Maguire found significantly more volume of grey matter in the posterior hippocampus in London taxi drivers than in a matched control group. This part of the brain is linked with the deevelopment of spatial and navigational skills. As part if their training, London cabbies take a complex test called the knowledge to assess their recall of city streets and possible routes. This learning experience appears to alter the structure of the taxi drivers brains. The longer they had been in the job, the more pronounced the structural difference
• Plasticity and learning

  Draganski imaged the brains of medical students three months before and after their final exams. Learning-induced changes were seen in the posterior hippocampus and the parietal cortex, presumably as a result of learning for the exam.
• Functional recovery of the brain after trauma

  Functional recovery of the brain after trauma is an important example of neural plasticity which is where healthy brain areas take over functions of areas that are damaged, destroyed or even missing. Neuroscientists suggest this process occurs quickly after trauma and then slows down at which point the person may require rehabilitative recovery.
• Functional recovery of the brain after trauma 


  The brain is able to rewire and reorganise itself by forming new synaptic connections close to the area of damage. Secondary neural pathways that would not typically be used to carry out certain functions are activated or unmasked to enable functioning to continue.
• Functional recovery of the brain after trauma 


  . Axonal sprouting - growth of new nerve endings which connect with other undamaged 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.

  . Recruiment of homologus areas - the opposite side of the brain takes over specific tasks e.g. language production.
• Evaluation - plasticity

  One limitation is possible negative behavioural consequences. The brain's adaption to prolonged drug use leads to poorer cognitive functioning in later life, as well as an increased risk of dementia. 60 - 80 %of amputees have phantom limb syndrome. This suggests that the brain's ability to adapt to damage is not always beneficial and may lead to physical and psychological problems.
• Evaluation - plasticity

  One strength of plasticity is that it may be a life long ability. Bezzola demonstrated how 40 hours of golf training produced changes in the neural representations in participants aged 40 - 60. Using FMRI, motor cortex activity in the novice golfers reduced compared to a control group, suggesting greater efficiency after training. This shows that neural plasticity can continue throughout the lifespan.
• Evaluation - Functional recovery of the brain after trauma 


  One strength is its real world application. Understanding plasticity has led to neurorehabilitation. Understanding axonal growth encourages new therapies. For example, constraint-induced movement therapies involves massed practice with an affected arm while the unaffected arm is restrained. This shows that research into functional recovery helps medical professionals know when interventions can be made.
• Evaluation - Functional recovery of the brain after trauma 


  One limitation is the neural plasticity may be related to cognitive reserve. Schneider looked at the time brain injury patients had spent in education and their chances of a disability-free recovery. 40% of patients who achieved DFR had more that 16 years in education compared to about 10% of patients who had less than 12 years in education. This suggests that cognitive reserve is a crucial factor in determining how well the brain adapts after trauma.