Plasticity Flashcards
What is plasticity?
The brain’s ability to change and adapt synapses, pathways and structures as a result of experience. This experience is usually positive, e.g. learning and memory involves brain plasticity. However brain plasticity can also involve the ability to adapt to damage caused by trauma from something like a road accident
Plasticity in new born
First year of infant is the most interesting. By the end of the first year, they have more nuerons and synapses by the time they fully mature. This is because their brain is exposed to so many new experiences and needs a lot of neurons to cope. Brain has a lot to learn. To the extreme, if in some case a baby is born with one hemisphere, or if it is removed, then by adulthood, there are no impairments.
Plasticity as a result of life experience
Nerve pathways that are frequently used develop stronger connections, those that are rarely used eventually die. By developing new connections and reducing weak ones, the brain is able to adapt to the changing environment. There is however a decline In cognitive function with age. Boyke taught 60 year olds a new skill, which increased their grey matter in the visual cortex
Plasticity and video games
Kuhn et al compared control group to those who had been given video game training for 30 mins for 2 month on super Mario. The game caused significant increases in grey matter in the visual cortex, hippocampus and cerebellum. Playing results in new synaptic connections in brain areas involved in spatial navigation, strategic planning, working memory and motor performance.
Meditation and plasticity.
Davidson et al compared eight practitioners of Tibetan meditation with 10 students of no meditation experience. EEG picked up more gamma wave activity in the practitioners, even before they started meditating. Gamma waves coordinate neural activity.
Strengths plasticity
+ research support in animals - kempermann et al found more new neurons in the brains of rats who had been placed in complex environments compared to those placed in basic housing. This increase was seen in the hippocampus, which is involved in the forming of new long term memories and the ability to navigate
+ maguire et al also measured grey matter in taxi drivers from London using MRI. Their hippocampus was hella larger than a control group and this was positively correlated with their time as a taxi driver.
Weaknesses plasticity
- problems of generalisation: rats are not same as humans so we can’t generalise
- studies on newborns carry ethical issues such as consent and harm, so caution is needed.
What is functional recovery?
A form of plasticity whereby if there is damage caused by some sort of trauma, the brain can redistribute or transfer the functions normally performed by that area, to other un damaged areas. When brain is still maturing, recovery from trauma is more likely, however, the brain is capable of plasticity and functional recovery at any age. Studies also found women recover quicker than men
What is it called when functions are transferred?
Neural reorganisation. Growth of new neurons or connections to compensate for damaged areas can also occur, this is neural regeneration. Axon sprouting is part of neural regeneration whereby new nerve endings grow and connect with other un damaged ones to form new neural pathways
When does spontaneous recovery from brain injury slow down?
After a few weeks, physiotherapy may be needed to maintain improvements in functioning. These might include movement therapy, electrical stimulation of the brain to counter deficits in motor and cognitive functioning that can be experienced following a stroke
Evaluation functional recovery
Phantom limb syndrome can be used as evidence of neural reorganisation. PLS is the continued experience of sensation in a missing limb, as if it were still there. These sensations are often unpleasant and painful. PLS is thought to be caused by neural reorganisation in the somatosensory cortex that occurs as a result of limb loss
Hubel and Torsten Wisel sewed one eye of a kitten shut and analysed the brains cortical response. They found that the visual cortex for the shut eye was not idle. It continued to process information from the open eye. This was further evidence that brain areas can reorganise themselves adapt their functions
