Plasticity and functional recovery

• What is plasticity?

  • Also known as neuroplasticity/cortical remapping
  • Describes brain's tendency to change and adapt as a result of experience and new learning
• What is functional recovery?

  • A form of plasticity
  • The brain's ability to redistribute or transfer functions (usually performed by damaged area) to other undamaged areas
  • Tends to reduce with age, childhood has greater propensity due to constant adaptation
• What is synaptic pruning?

  • As we age, rarely used synaptic connections are deleted
  • Frequently used connections are strengthened
• During infancy, the brain experiences a rapid growth in the number of synaptic connections it has. Peak of 15,000 at 2-3 years
• What research supports the idea of plasticity? (AO1/AO3)

  • Maguire taxi driver study
  • Found more volume of grey matter in posterior hippocampus than matched controls
  • Suggests that PH is associated with development of spatial and navigational skills
  • Its likely new synaptic connections were formed to achieve faster processing for taxi drivers to revise a route
  • Longer in the job, more pronounced structural difference, therefore supports plasticity within brain
• What research supports the idea of plasticity? (AO1/AO3) med school students

  • Draganski et al
  • Imaged brains of med students 3 months pre and post final exams
  • Found learning induced changes in posterior hippocampus and parietal cortex
  • Supports the idea of plasticity as its likely the brain formed new synaptic connections for the information revised and stored creating easy access for recall
• What is spontaneous recovery?

  • Where the unaffected areas of the brain quickly adapt and compensate for damaged areas
  • Initially rapid, it slows down after weeks/months
  • More likely for children due to brain's ability to adapt
• What is neural reorganisation?

  • The transfer of functions to undamaged areas
  • May explain how people recover from trauma
• What are the 3 structural changes that occur in functional recovery?

  • Axonal sprouting
  • Reformation of blood vessels
  • Recruitment of homologous areas
• What is axonal sprouting?

  • The growth of new nerve endings
  • Connects with other undamaged nerve cells to form new neuronal pathways
  • Strengthens existing pathways or repairs damaged pathways to restore functionality
• What is reformation of blood vessels?

  Supports axonal sprouting by supporting the new neuronal connections made, strengthens repair process
• What is recruitment of homologous areas?

  • Recruitment of similar areas on the opposite side of the brain to perform specific tasks
  • More often in children than adults
  • However this may result in a loss of original functionality, resulting in less effective as a result
• Case study supporting functional recovery (AO3)

  • Jody Miller
  • Epileptic seizures resulted in loss of motor function in left arm and leg
  • Had a hemispherectomy, removal of right hemisphere
• Apply recruitment of homologous areas to Jody Miller's case

  • Since Jody's right hemisphere was removed, her left hemisphere’s homologous areas took on new roles that her right would usually.
  • E.g. motor functioning and spatial processing.
  • This reallocation of function across hemispheres is crucial in helping the brain compensate for significant losses.
• Apply process of axonal sprouting to Jody Miller's case

  • Neurons in her left hemisphere would have extended new axons to areas that would have relied on her right hemisphere.
  • This is particularly effective in young brains, helping with Jodie’s ability to walk and balance which her seizures previously effected.
  • This adaptation highlights the role of plasticity in neural recovery.
• What is dernervation supersensitivity?

  • To compensate for the loss of axons in a pathway, the remaining axons become more sensitive
  • Therefore more likely to experience side effects such as pain
• What are factors that make functional recovery more likey?

  • Age, children have the best ability to recover then young adults
  • Gender, women are more able to recover from brain damage
  • Rehabilitative therapy, focused effort results in neural improvement
• What is constraint induced therapy?

  • This stops patients from using coping strategies (e.g. using undamaged limbs for tasks or body language to communicate)
  • Helping them improve via functional reorganisation/recruitment of homologous areas
• How does maguire support plasticity?

  • Suggests that the physical structure of the brain is plastic and is able to reconfigure itself to adapt to psychological demands in case to improve memory formation
• What is a strength of plasticity and functional recovery? (AO3)

  • Real life app
  • Practical benefits such as the development of rehabilitative therapy
  • has helped sufferers with cases of brain damage to return to work after recovery with better functioning
  • Benefitting the wider economy as more people working = more money paid back into the country
• Strength of plasticity(AO3)

  • Age
  • Functional plasticity tends to reduce with age
  • The brain has greater propensity for reorganisation in childhood due to constant adaptation from new experiences
  • BEZZOLA et al found 40 hours of golf training produced changes in neural representations of movement
  • This was in 40-60 year olds
  • FMRI found reduced motor cortex activity in novice golfers compared to control group
  • Suggests there were more efficient neural representations after training, therefore plasticity is not limited to an early lifetime, it continues
• Strength to support functional recovery (AO3) GG

  • Case study of Gabby Giffords, longitudinal study
  • Survived assassination when shot in the right hemisphere
  • After being placed in a waking coma, her brain had compensated for functions within months
  • Under supervision, regained control of her left arm and leg, could write and read
  • Able to read and speak short phases
  • Supporting evidence as its likely she had experienced AS, RHA, RFBV
  • 41 years old, was able to make a full recovery which is aytpical due to her older age
  • Therefore supports process of FR and the fact this can occur at an older age
• Limitation- negative plasticity (AO3)

  • The brain's ability to rewire itself is not all positive and may result in maladaptive consequences
  • Prolonged drug use has resulted in poorer cognitive functioning and increased risk of dementia (MEDINA)
  • 60-80% of amputees develop phantom limb syndrone
  • Continued experience of sensations in the missing limb, painful and may be a result of faulty cortical reorganisation in the somatosensory cortex (RHA)
  • Therefore limitation as challenges idea that plasticity is entirely positive and beneficial