biopsych - plasticity and functional recovery - y13 Flashcards
what is plasticity?
cortical remapping. the brains tendency to change and adapt 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 functions usually performed by a damaged area to other undamaged areas.
gopnick et al (1999)
during infancy, the brain has a rapid growth in the number of synaptic connections: at birth, the number of synapses per neuron is 2,500, but by age 2 or 3, its about 15,000 per neuron. twice as many as there are in the adult brain. as we age, those connections that have rarely been used are deleted while those that we do use are strengthened - synaptic pruning
what is synaptic pruning?
as we age, connections which have rarely been used are deleted and those that are used often are strengthened.
research into plasticity Maguire et al (2000) london taxi
found London taxi drivers to have significantly more grey matter volume in the posterior hippocampus (spatial and navigation skills) than a matched control group the longer they had been in the job the larger the structural difference. learning the ‘knowledge’ appears to change the structure of brains.
research into plasticity Draganski et al (2006)
imaged the brains of medical students three months before and after their final exams. learning induced changes occurred in the posterior hippocampus and the parietal cortex.
what did mechelli et al (2004) find?
found a larger parietal cortex in the brain of bilingual people compared to matched monolingual controls.
explain how functional recovery occurs in the brain after trauma
following trauma such as physical injury or a stroke, unaffected areas of the brain adapt and compensate for the damaged areas. this functional recovery is an example of neural plasticity. healthy brain areas can take over the functions of damaged, destroyed or missing areas. this can occur quickly after trauma (spontaneous recovery) and then slow down after many weeks or months.
what happens in the brain during recovery?
the brain reorganises and rewires itself by forming new synaptic connections close to the damaged area.
doige (2007)
secondary neural pathways that would not be typically used to carry out certain functions are activated to enable functioning to continue.
what is axonal sprouting?
the growth of new nerve endings which connect with other undamaged nerve cells to form new neural pathways.
what is the recruitment of homologus areas?
refers to areas on the opposite side of the brain to perform specific tasks. so if the brocas area was damaged on the left side of the brain, the right sided equivalent would carry out its function. functionality may then shift back to the left side in the future.
what is denervation supersensitivity?
a phenomenon that occurs when neurons are lost, causing the post-synaptic membrane to develop more receptors for neurotransmitters in order to compensate
important practical applications? - strength
this knowledge had let to important practical applications such as neurohabilitation: following brain trauma spontaneous recovery slows down after a few weeks, so physical therapy may be needed to maintain any improvements. for example, movement therapy, electrical stimulation of the brain to counter cognitive deficits. another example could be constraint-induced movement therapy. this is used with stroke patients whereby they repeatedly practice using the affected part of their body while the unaffected part is restrained.
medina et al (2007)
our understanding of the processes involved in plasticity have allowed us to understand how the brains ability to rewire itself can also have maladaptive consequences: extensive drug use can lead to deficits in cognitive functioning, and higher risk of dementia in later life.
