Biopsychology - Brain plasiticity

• Plasticity / Neuroplasticity / Cortical Remapping


  The brain's tendency to change and adapt both functionally and physically as a result of experience and new learning. The brain has the ability to change throughout life.
• Functional Recovery


  A form of plasticity. Following damage or trauma, the brain's ability to redistribute or transfer functions usually performed by a damaged area(s) to other, undamaged area(s).
• Brain Plasticity

  • During infancy, the brain experiences a rapid growth in the number of synaptic connections it has, peaking at approximately 15,000 at age 2-3. This is approximately twice as many as there are in an adult brain.
  • As we age, rarely used connections are deleted and frequently used connections are strengthened – synaptic pruning.
  • Originally, it was thought that these changes were restricted to the developing brain within childhood, and the adult brain having moved past critical period would remain fixed and static – in terms of function ad structure. However, recent research has shown that at any time in life existing neural connections can change or new neural connections can be formed as a result of learning and new experiences – plasticity.
• Voxel Based Morphometry (VBM)

  3D measure of volume and density of grey matter
• Pixel Counting


  2D measure of the size of grey matter in the hippocampus
• Maguire et al (2000) study


  • Experimental group: 16 right-handed male London taxi drivers who had been driving for a minimum of 1.5 years. Age range was between 32-62 years old. All of the taxi drivers had healthy general medical, neurological, and psychiatric profiles.
  • Control group: Scans of 50 healthy right-handed males who did not drive taxis were included for comparison. Matched pairs design was used.
  • The taxi drivers brains were scanned in a structural MRI scanner and then compared to the 50 brain scans in the control group.
• Functional Recovery


  • Functional recovery is the idea that following physical injury or other forms of trauma, unaffected areas of the brain can adapt to compensate for those that are damaged.
  • Functional recovery is an example of brain plasticity – healthy brain areas may take over the functions of those areas damaged, destroyed or missing.
  • Neuroscientists suggest this process can happen quickly after trauma (spontaneous recovery) and then slow down over several weeks or months.
• Functional Recovery


  • Case studies of stroke victims who have experienced brain damage and thus lost some brain functions have shown that the brain has an ability to re-wire itself with undamaged brain sites taking over the functions of damaged brain sites. Neurons next to damaged brain sites can take over at least some of the functions that have been lost.
• Functional Recovery

  1. Axonal sprouting: the growth of new nerve endings which connect with other undamaged nerve cells to form new neural pathways.

  2. Reformation of blood vessels.

  3. Recruitment of homologous (similar) areas on the opposite side of the brain to perform specific tasks: for example if Broca's area was damaged on the left side of the brain, the right sided equivalent would carry out its functions – after a period of time functionality may shift back to the left.

  4. Neuronal unmasking: Wall (1977) noticed the brain contained 'dormant synapses' – neural connections which have no function. However, when brain damage occurs these synapses can become activated and open up connections to regions of the brain that are not normally active and take over the neural function that has been lost as a result of damage.
• Functional Recovery and Age


  There is a negative correlation between functional recovery and age: i.e. young people have a higher ability to recover which declines as we age.
• Level of Education and Speed of Recovery


  Level of education (associated with a more active, neurologically well-connected brain) is positively correlated with speed of recovery from traumatic brain injuries. Schneider found that patients with a college education were x7 times more likely than those who did not finish college to recover from their disability after 1 year.
• Phantom Limb Syndrome


  • 60-80% of amputees have reported continued experience of sensations in their missing limb – as if it was still there. These are unpleasant, painful & thought to be due to the cortical reorganisation in the somatosensory cortex that occurs as a result of limb loss.
• Plasticity & Functional Recovery Explained
• Maguire et al (2000) Explained