plasticity Flashcards
plasticity definition
descries the brain’s tendency to change and adapt as a result of experience and new learning. this generally involved the growth of new connections
how is the brain seen as plastic
it has the ability to change throughout life
the brains plasticity in infancy
the brain experiences a rapid growth in the number of synaptic connections it has, peaking at about 15000 per neuron at 2-3 years at age (Gopnik et al 1999). this is about twice as many as there are in the adult brain
synaptic connections as we age
as we age rarely-used synaptic connections are deleted and frequently used connections are strengthened which is a process called synaptic pruning
what did people once think about plasticity
adult brain was not capable of change but we now understand synaptic pruning allows lifelong plasticity where new neural connections are formed in response to new demands of the brain
who did research in to plasticity by studying brains of London taxi drivers
Maguire et al
when did Maguire et al research plasticity
2000
what did Maguire at al find about plasticity in London taxi drivers brains
significantly more volume if grey matter in the posterior hippocampus than in a matched control group
what the function of the posterior hippocampus
part of the brain associated with the development of spatial and navigational skills in humans and other animals
what requires the London taxi drivers to have more grey matter in the posterior hippocampus
take a complex test as part of their training called the knowledge. this assess their abilities to recall the city streets and possible routes
what did Maguire et al find a positive correlation between
longer the taxi drivers has been in the job, the more pronounced the structural difference of their brain was
who’s findings were similar to Maguire at al
Draganski et al 2006
what was Draginski et al’s research on plasticity
imagined brains of medical students 3 months before and after their final exams.
Dragniski et al findings
learning-induced changes were seen to have occured in the posterior hippocampus and the parietal cortex which was presumed to be as a result of learning (medical stundents)
limitation of plasticity - negative plasticity
-may have negative behavioural consequences
-evidence has shown that the brain’s adaptation to prolonged drug use leads to poorer cognitive functioning later in life, as well as an increased risk of dementia (Medina et al 2007)
-60-80% of amputees have been known to develop phantom limb syndrome which is the continued experience of sensations in the missing limbs as if it were still there. these are usually unpleasant and painful which are thought to be due to cortical reorganisation in the somatosensory cortex which occurs as a result of limb loss (Ramachandran and Hirstein 1998) –> suggests that the brain’s ability to adapt to change is not always beneficial
