7. Brain Plasticity + Functional Recovery After Trauma

• 1. Brain Plasticity + Functional Recovery

  Brain Plasticity - ability to change/adapt as result of experience.

  • brain creates new neural pathways + adapts to old ones as consequence of learning.
  • 3y/o, approx 15,000 diff brain connections; as age, unused ones ‘die’, while used are strengthened = ‘synaptic pruning’.
  • Boyke (2008), increase in grey matter of 60y/o taught to juggle; growth reversed when stopped practicing = plasticity.
• 2. Brain Plasticity + Functional Recovery

  Maguire et al. (2000):

  • brains of London taxi drivers = more volume of grey matter in posterior hippocampus than control grp.
  • this part brain associated w/ development of spatial/navigational skills.
  • London taxis must take test, assessing their recall of streets/routes; altered structure of their brains.
• 2a. Brain Plasticity + Functional Recovery

  Draganski et al. (2006):

  • investigated brains of 3 medical students 3 months before/after exam.
  • learning changes occurred in posterior hippocampus + parietal cortex due to exam.
• 2b. Brain Plasticity + Functional Recovery

  Mechelli et al. (2004):

  • found larger partial cortex in brains of bilingual people compared to monolingual control grp.
• 3. Brain Plasticity + Functional Recovery

  Functional Recovery - idea certain abilities of brain may be moved rather than lost after trauma.

  • e.g. neural plasticity - stroke, unaffected areas compensate for damage.
  • spontaneous recovery - happens after trauma, but slows down so person needs rehabilitation therapy to recover.
• 3a. Brain Plasticity + Functional Recovery

  Doige (2007) - Neural Unmasking:

  • synapses blocked bc rate of neural input too low to be activated.
  • unmasking happens when areas damaged so rate of input to synapse increases.
  • opens connections to brain regions that aren’t normally activated = gives way to development of new structures.
• 3b. Brain Plasticity + Functional Recovery

  Types of Structural Changes:

  • axonal sprouting - growth new nerve, connects w/ other undamaged nerve cells to form new neural pathways.
  • reformation of blood vessels - flow of o2 blood to affected ares begins reform broken vessels.
  • recruitment of homologous areas - similar areas on opposite side brain used to perform specific tasks (e.g. damage to Broca’s LH; right side equivalent would carry out language functions).
• 3c. Brain Plasticity + Functional Recovery

  Stem Cells - unspecialised cells that have potential to give rise to diff cell types that carry diff functions; used in treatment for trauma:

  A - implant into brain to replace dead calls.

  B - cells secrete growth factors that rescue injured cells.

  C - transplanted cells form neural network, links uninjured brain site (where new stem cells made w/ damaged area).
• Brain Plasticity + Functional Recovery (Evaluation)

  Strength:

  P - understanding plasticity process contributed to field of neurorehabilitation.

  E - after injury, spontaneous recovery slows down so forms of physical therapy required to maintain improvements.

  E - e.g. movement therapy + electrical stimulation, counter deficits in motor/cognitive functioning.

  L - brain has capacity to ‘fix itself’ but needs further intervention if to be fully successful (real-life/practical app in clinical practice).
• Brain Plasticity + Functional Recovery (Evaluation)

  Strength:

  P - functional plasticity reduce w/ age.

  E - Bezzola (2012); 40hrs golf training = changes in neural representation of movement in participants (40-60y/o).

  E - fMRI; reduced motor cortex activity compared to control, suggest more efficient neural rep after training.

  L - shows plasticity continues throughout lifespan.
• Brain Plasticity + Functional Recovery (Evaluation)

  Strength:

  P - animal study support; Hubel + Wiesel (1963).

  E - sewed one eye of kitten shut :( + analysed brain’s cortical responses.

  E - visual cortex associated w/ shut eye not idle, but continued process info.

  L - animal studies important in modern plasticity + functional recovery research.

  Limitation:

  P - ethical issues of harm to animals - does this outweigh benefits of research though?