Plasticity and Functional Recovery Flashcards
Brain plasticity
Brain is described as plastic due to ability to change throughout life. Infancy growth in number of synaptic connections. Whilst aging the rarely used connections are deleted and the more often used ones are strengthened - Synaptic pruning. New neural connections can be formed in response to new demands new demands on the brain.
Research into plasticity.
Maguire et al
London taxi drivers. Found significantly higher volume of grey matter in the posterior hippocampus compared to matched control group. Posterior hippocampus is associated with spatial and navigational skills. London cab test ‘he knowledge’ learning routes test alters the structure of the drivers brain. The longer the drivers worked the more prominent the structural difference of the brain.
Limitation of plasticity
Negative behavioural consequences.
Medina et al
Prolonged drug use leads to poorer cognitive functioning later and increases risk of dementia.
60%-80% of amputees develop phantom limb syndrome. Feeling sensations as if the limb was there. Due to cortical reorganisation in the somatosensory cortex Ramachandran and Heinsten. Brain adapting to environmental changes is not always beneficial.
Strength of plasticity
It is a life long ability.
Bezzola
40 hours of golf training produces changes in neural representations of movement in participants aged 40-60. FMRI shows increased motor cortex activity compared to control group. Evidence for plasticity and its continuance.
Strength
Draganski
Supporting evidence for plasticity. Imaged brains of medical students before and after finals. Learning is what was presumed to cause he changes found in the posterior hippocampus and parietal cortex.
Functional recovery
After bran trauma ( injury or stroke) Unaffected area of brain adapt to help out (compensate) areas that are effected. Occurs due to plasticity. Can occur quickly after trauma (spontaneous recovery) then slow down to weeks and months. Rehabilitative therapy is then usually introduced.
During functional recovery
New synaptic connections are formed. Secondary neural pathways are unmasked or activated.
Axonal sprouting
New nerve ends grow and connect with other undamaged nerve cells to form neural pathways.
Denervation super sensitivity
Axons that do similar jo to the damaged ones become aroused at higher level to compensate for lost ones. Can be bad e.g. oversensitivity to pain.
Recruitment of homologous areas on opposite side of brain
Specific tasks can still be performed. E.g. function of broca’s area in left hemisphere can be carried out by right hemisphere. Functionality may shift back to the right after a while or recovery.
Strength of functional recovery. Real world application.
Neurorehabilitation. Axonal growth encourages new therapies to be tried. Constraint induced movement therapy, unaffected part is restrained and effected part is used to best of ability. Research into functional recovery is helpful. Paves way for intervention and treatment.
Limitation of functional recovery
Schenider
Level of education may effect recovery rates. The more time someone spent in education the higher the likelihood of Disability free recovery (DFR). Amount of time in education is an indication of their cognitive reserve. 40% of those who achieved DFR had more than 16 years of education. 10% of those who achieved DFR had less than 12 years.
Those with lower cognitive reserves have smaller chances of DFR.
Nature of research into functional recovery
Banerjee
Treated sufferers of stroke with stem cells. All participants recovered compared to only 4% in typical recovery. Drew conclusion only on 5 participants. This is normal compared to other research into functional recovery. Small sample sizes being typical across functional recovery studies may be a problem.
