Plasticity and functional recovery of the brain after trauma Flashcards
Define plasticity
This describes the brain’s tendency to change and adapt as a result of experience and new learning. This generally involves the growth of new connections.
What is plasticity also known as?
neuroplasticity and cortical remapping
What did Gopnick et al find?
In infancy, the brain experiences growth in the number of synaptic connections it has, peaking at around 15,000 at age 2-3. This is twice as many as in the adult brain.
Define functional recovery
A form of plasticity. Following injury, unaffected areas of the brain are able to adapt and compensate for those areas that are damaged. As we age, rarely used connections are deleted and frequently used connections are strengthened in a process known as synaptic pruning.
What does synaptic pruning enable?
Enables lifelong plasticity where new neural connections are formed in response to new demands on the brain.
Give an example of plasticity in young humans
Sometimes a human baby is born with one extremely damaged hemisphere. If this hemisphere is removed at birth the baby has only one half of their brain… yet this results in few or no cognitive impairments.
Functions (e.g. language if the left hemisphere is removed) are transferred to the surviving brain areas. This is amazing evidence of plasticity.
What was originally thought about brain plasticity?
It was originally thought that such changes were restricted to the developing brain within childhood, and that the adult brain, having moved beyond a critical period would remain fixed and static in terms of function and structure.
However what does research suggest?
research suggests that at any time in life existing neural connections can change, or new neural connections can be formed, as a result of learning and experience. Therefore brain plasticity continues into adulthood.
Who did research into plasticity?
Eleanor Maguire and Draganski et al
What did Maguire study?
studied the brains of London taxi drivers and compared them against a control group. This is because taxi drivers have to remember the map of London’s streets.
What did Maguire find?
found significantly more volume of grey matter in the posterior hippocampus in the taxi drivers than in a matched control group. Maguire et al. also found a positive correlation between the size of the posterior hippocampus and the time as a taxi driver = the longer they had been in the job, the more pronounced the structural difference was.
What is the posterior hippocampus associated with?
This part of the brain is associated with the development of spatial and navigational skills in humans and other animals. This difference shows plasticity.
Why did the taxi drivers have more grey matter in the posterior hippocampus?
As part of their training London cabbies must take a complex test called ‘The Knowledge’, which assesses their recall of the city streets and possible routes (including all hotels, hospitals, etc). It appears that this spatial learning alters the structure of the taxi drivers’ brains.
What did Draganski et al do?
imaged the brains of medical students 3 months before and after their final exams.
What did Draganski et al find?
Learning-induced changes were seen to have occurred in the posterior hippocampus and the parietal cortex, presumably as a result of studying for exams (medical students need to learn an awful lot!)
