Plasticity

• What is Plasticity?


  - Brain's ability to change and adapt to experience

  - Nerve pathways used frequently develop stronger connections, rarely used neurons die

  - Natural decline to in cognitive functioning with age tho Boyke found evid. of plasticity in 60 year olds taught a new skill
• Discuss research into Plasticity

  - Kuhn:

  ○ P: Control group vs training group that played Mario Kart for at least 30 mins a day for 2 months

  ○ F: Sign. increase in grey matter in cortex, hippocampus and cerebellum, not evident in control gap

  ○ C: Video game had resulted in new synaptic connections in brain areas involved w/spatial nav, strategic planning, memory and motor perf.

  - Davidson:

  ○ A: Demonstrate that meditation can change inner workings of brain

  ○ P: 8 Tibetan monks vs 10 student volunteers, fitted w/electrical sensors and asked to meditate

  ○ F: Found much greater activation of gamma waves (coordinate neuron activity) in monks, students only showed slight increase in activity while meditating

  ○ C: Changes working in brain, may even do so permanently (monks had higher gamma wave activity even before meditating)

  ○ E: Correlational? Small sample size, not generalisable (lil. eco. validity)

  - Maguire:

  ○ P: 11 Licensed London taxi drivers, all male, all right-handed, mean age 45 years, avg time spent working 14.55 years, no prev history of neurological and psychiatric illness, had informed consent, required to complete four recall tasks, s controls, all ppts performed all taks, all blindfolded, all digitally recorded, repeated measures design, PET scans taken over period of 90 seconds after task

  ○ F: Right temporal region was always activated during any of these tasks, during recall of routes and landmarks, right hippocampus was significantly activated over all other areas

  ○ C: Hippocampus significantly larger than control puts, and volume positively correlated w/amount of time they'd been taxi driver

  ○ E: Correlational, Gender-bias(beta), High ecological validity, Small sample size, Objective experiment
• What is Functional Recovery?


  - Recovery of abilities and compromised mental processes as result of brain injury/disease

  - Happens in 2 ways:

  ○ Neuron Unmasking: Wall, 'dormant synapses', exist but func. blocked, increasing rate of input would active them, which occurs when brain areas around become damaged, leading to the 'masking' of these synapses opening connections to diff. regions of brain

  ○ Stem Cells: Unspecialised cells, may directly replace dead/dying cells, secrete growth factors that 'reduce' injured cells, form neural network linking uninjured brain site to damaged region allowing carrying out of func.
• Evaluate Functional Recovery


  ✓ Tajiri prov. svid for role of stem cells → Assigned rats w/traumatic brain injury to 2 groups, 1 receiving stem cells to affected area, 1 received empty solution, stem cell rats showed clear development

  ✓/✗ Huttenlocker, plasticity reduces with age →studies have suggested that some abilities can still be modified in adults with intense retraining → Elbert capacity for neural reorganisation still greater in children than adults

  - Schneider, patients w/ college edu 7x mor likely than those who didn't finish high school to be disability-free after one year of mod-ext. brain injury