PLASTICITY AND FUNCTIONAL RECOVERY OF THE BRAIN AFTER TRAUMA

• The brain is like plastic - it can change throughout life.
• By the age of 2-3 years old, the brain has about 15,000 synaptic connections (twice as many as in the adult brain). The brain is more plastic at an early age as we are learning more. 

  This is because as we get older synaptic connections that we do not use are deleted; those we use frequently are strengthened: synaptic pruning (forming habits). 

  It was originally thought that after a critical period the brain would remain fixed in relation to structure and function. 
• However, it seems that at any point in life, existing neural connections can change, and new connections can be formed due to learning and experience (going to school, loss of loved one, learning a new language, travelling) = plasticity. 
• MAGUIRE ET AL (2000) - Driving


  They studied the brains of London taxi drivers and found more grey matter in the posterior hippocampus in them than in a matched control group (taxi drivers elsewhere). This part of the brain is associated with navigational skills e.g. routes and directions as London taxi drivers must have extensive knowledge of the area. The learning of routes is altering taxi drivers brains and the longer they have been driving, the more pronounced the difference.
• DRAGINSKI ET AL (2006) - Education


  They imaged the brains of medical students three months before and after their final exam and found that there were changes in the posterior hippocampus and the parietal cortex. This was thought to be a result of learning for their final exam.
• MECHELLI ET AL (2004) - Language


  They found a larger parietal cortex in the brains of people who were bilingual compared to matched monolingual controls.
• Mindfulness


  It can be used to reduce stress but may also alter the structure and function of the brain.
• LAZAR ET AL (2005)


  MRI scans showed that experienced meditators had a thicker cortex than non-meditators, particularly in areas related to attention and sensory processing as it teaches patience.
• HOLZEL ET AL (2011) 


  Asked participants to take part in an 8-week mindfulness course. Afterwards, participants had more grey matter in the left hippocampus - the part of the brain associated with learning and memory.
• TANG ET AL (2012)


  Four weeks of meditation resulted in an increase in white matter in the anterior cingulate cortex - part of the brain that contributes to self-regulation and control.
• Functional recovery of the brain after trauma

  1. Following injury or trauma, unaffected brain areas can often adapt and compensate for damaged areas. For example, after a stroke. This functional recovery is AN EXAMPLE of plasticity. 
  2. Healthy brain areas take over the functions of the damaged/destroyed areas. 
  3. This can happen quickly after trauma = spontaneous recovery. 
  4. Recovery may then slow down and require the patient to have rehabilitative therapy to aid recovery. 
• Recovery of the brain


  The brain forms new synaptic connections close to the area of damage. In addition, secondary neural pathways not normally used are activated to enable the function to continue. 
• There are also structural changes to the brain:

  • Regeneration: axonal sprouting: growth of new nerve endings, they connect to other undamaged nerve cells to form new pathways. 
  • Reformation of blood vessels. 
  • Recruitment of homologous (similar) areas: on the opposite side of the brain. After a while, the function may switch back to the original side. 
  • Denervation super-sensitivity to reduce the severity/extent of impairment. 
• EVALUATION:

  ✅Practical application 

  ✅Age and plasticity 

  ✅Seasonal brain changes 

  ❌Negative consequences of plasticity 

  ❌Functional recovery and cognitive reserve