Plasticity and functional recovery

• Placticity from life experience

  • Through new experiences, nerve pathways that are used frequently develop stronger connections, and infrequently used ones die eventually
  • Through making new connections and pruning weak ones, the brain can constantly adapt to a changing environment
  • Age brings natural decline in cognitive function, and the brain changes
  • Boyke et al 2008, 60 yr olds still had plasticity, increased grey matter in visual cortex after learning juggling
• Plasticity through video games

  • Kühn et al 2014, control group and group who played super Mario at least 30 mins per day for 2 months
  • Increased grey matter in cortex, hippocampus, and cerebellum of gaming group
  • Concluded that gaming brought new synaptic connections involved in spatial navigation, strategic planning, working memory, and motor performance
• Plasticity through meditation

  • Davidson 2004, 8 Tibetan monks Vs 10 control volunteer students
  • Fitted with electrical sensors and asked to meditate
  • Electrodes picked up greater activation of gamma waves (neuron activity) in monks, while waves in students only slightly increased
  • Meditation can have longer term effects, monks had higher rate of gamma waves even when not meditating
• Functional recovery

  • In 1960s, researchers studied stroke victim cases where functioning was recovered
  • Discovered when brain cells are damaged or destroyed during the stroke, the brain can rewire itself over time to regain a level of control
  • Even if some parts are destroyed, other brain areas take over the lost functions - neurons next to damaged areas forming new circuits to resume function
• Neural unmasking

  • Wall 1977, identified dormant synapses in the brain. They always existed anatomically, but functioning is blocked under normal circumstances (ineffective due to lack of neural input)
  • If surrounding area becomes damaged, neural input rerouted to to dormant synapses, opening/unmasking them
  • These new connections can open regions of brain normally inactive, creating a lateral spread of activation and giving way to development of new structures
• Stem cells

  • Many views on how unspecialised stem cells may provide treatment for brain damage of neurodegenerative disorders

  1. Stem cells implanted into brain w lot uld directly replace dead or dying cells
  2. Transplanted cells secrete growth factors that somehow rescue injured cells
  3. Transplanted cells form a neural network, linking an uninjured brain site, where new stem cells are made, with a damaged brain region
• AO3 Plasticity

  • Kempermann et al 1998
  • Increased number of new neurons in rats housed in complex environments compared to ratsin lab environments, specifically in hippocampus region (related with navigation and new memories)
• AO3 Plasticity

  • Maguire et al 2000, London taxi drivers
  • MRI scans of taxi drivers and control Ps
  • Posterior hippocampi of drivers had significantly more grey matter (were larger) than control
  • Hippocampal volume positively correlated with amount of time they had been drivers
• AO3 Functional recovery

  • Tajiri et al 2013, rats with brain trauma, split into two groups
  • One received stem cells into damaged region, one received a solution with no stem cells into brain region
  • Three months after, rats with stem cells showed clear development of nueronlike cells in injury site, with a solid stream of stem cells migrating to the brain's site of injury (none of this evident in other group)
• AO3 Functional recovery

  • Huttenlocher 2002, functional plasticity reduces with age
  • According to this view, only option after childhood for brain injury is to develop compensatory behavioural strategies (seeking social support, developing strategies to deal with cognitive deficits, ect)
  • However, other studies suggest with intensive retraining certain abilities can be recovered in adults
• AO3 Functional recovery

  • Schneider et al 2014, patients with equivalent of college education 7x more likely to be disability free one year after traumatic brain injury than those who didn't finish highschool
  • Retrospective study with US Traumatic Brain Injury Systems Database. 769 Ps studied, 214 disability free after 1 year
  • 39.2% of Ps with 16+ yrs of education disability free
  • 30.8% with 12-15 yrs were disability free
  • 9.7% with less than 12 yrs were disability free
  • Researchers theorise building up a cognitive reserve was an important factor in neural adaption during brain recovery