Plasticity

• what is brain plasticity?

  the brains tendency to change and adapt (functionally and physically) as a result of experience and new learning
• what is functional recovery?

  a form of plasticity. Following damage through trauma, the brains ability to redistribute or transfer functions usually performed by the damaged region to undamaged area
• what happens in the brain during the first 2-3 years?

  during the first 2-3 years the brain has a rapid growth in number of synaptic connections reaching 15,000 (2x as many as adult brain)
• what is synaptic pruning?

  - rarely used connections are deleted as we age and frequently used connections are strengthened

  - synaptic pruning happens throughout life as a result of learning and experience (not just childhood)
• what is functional recovery of the brain after trauma?

  - after physical injury or other trauma e.g. a stoke, unaffected (healthy areas) of the brain can adapt and compensate for the damaged areas - often happens quickly after trauma (spontaneous recovery) but then slows down - brain rewires forming new neural connections close to the area of damage
• how does the brain rewire?

  - axon sprouting : the growth of new axon endings, which connect to other nerve cells, creating new pathways

  - reformation of blood vessels

  - recruitment of homologous (similar) areas on the opposite side of the brain e.g. Brocas area
• how does the case of Jodi support brain plasticity?

  - had a hemispherectomy - removed right hemisphere- left hemisphere took over functions normally performed by right hemisphere- recovery for motor activity
• how does the case of EB support brain plasticity?

  - left hemispherectomy- lost his speech abilities and IQ was lowered- after recovery language fluency improved but he had dyslexia and some grammatical problems- right took over left functions
• why is it hard to generalise from case studies for brain plasticity?

  - Jodi and Eb were young so brains show greater plasticity than older people so can't assume all peoples brains will recover in the same way- didn't fully recover so even though other parts of brain took over functions suggests they aren't as well adapted
• what are strengths of brain plasticity?

  - case study supports

  - practical applications -- neurorehabilitation - techniques e.g. electrical stimulation and movement/ speech therapy helps the brain rewire
• what are limitations of brain plasticity?

  - negative plasticity - not all plasticity is a good thing e.g. Phantom limb syndrome - generalisations from case studies
• how does Maguire et al's study support brain plasticity?


  - London taxi drivers had significantly more volume in the posterior hippocampus compared to controls- linked to navigation and spatial memory skills - brains form new connections due to new learning- positive correlation between length of time being a taxi driver and volume- BUT correlation does not equal causation -- may be a taxi driver due to larger hippocampus
• how does Bezzola et al's study support brain plasticity?

  - gave 40 hours of training to novice golfers aged 40-60

  - measured function of motor cortex before and after training - found motor cortex gets smaller because movement becomes automatic

  - shows the brain is adapting and changing in response to new knowledge

  - plasticity continues with age