Plasticity

• Brain Plasticity

  The brains tendency to change and adapt because of experience and learning
• Maguire et al (2000)

  Aim

  • investigated brains of london taxi drivers and found significantly more grey matter on posterior hippocampi compared to control group

  Procedure

  • 16 london taxi drivers able to navigate without a map
  • Healthy men with a mean age 44 (14+ years experience)
  • Control group of 50 non taxi drivers
  • IV occurred naturally (Quasi experiment)
  • Matched pairs
  • MRI scans used

  Findings

  • The longer they were a taxi driver, the more pronounced the structural differences on right posterior hippocampi
  • positive correlation
• Maguire et al (2000) strengths

  • Highly controlled procedure
  • MRI scans - scientific credibility
  • Highly replicable
  • Quasi - high internal validity
  • Explanatory power of research is high
  • Navigational ability can be learned
  • Extraneous variables were minimised through matched pairs
  • Animal research support
• Maguire (2000) weaknesses

  • Ethnocentric sample
  • Highly skilled sample? Different cities?
  • Only UK based so lacks population validity
• When does plasticity occur?

  • Boyke et al (2008) - learning a new skill
  • Maguire et al (2000) - having a skilled job
  • Kuhn et al (2014) - playing video games
  • Davidson et al (2004) - Meditation
• Draganski et al (2006)

  • Imaged the brains of medical students before and after their final exams, found that learning induced changes were seen to have occurred in the posterior hippocampus and parietal cortex
• Functional recovery


  A form of plasticity where the brains ability to redistribute or transfer functions due to damage through trauma
• Synaptic pruning


  As we age, rarely used connections are deleted and frequently used connections are strengthened
• Axonal sprouting


  Undamaged axons grow new nerve endings to reconnect neurons whose links were injured or severed
• The recruitment of homologous areas


  Regions on opposite sides of the brain take on functions of damaged areas
• Functional recovery medically:

  Stem cells can be

  • implanted directly to replaced a damaged or missing cell
  • implanted next to a damaged area so the growth factories they secrete can try to repair them
  • To create a pathway around the damage - rerouting the communication to an uninjured area which could takeover the function
• Animal research support for plasticity

  Kepperman et al (1988)

  • Gave one group of rats complex and enriching houses, then the others had a standard lab cage
  • Rats with complex environment had larger hippocampi - supporting plasticity
  • Argued it was because of the need for memory and spatial navigation