plasticity + functional recovery

Neural plasticity

Brains ability to change or adapt as a result of experience or trauma

Functional recovery

A form of neural plasticity - ability of the brain to move or redistribute certain functions following trauma or damage.

London taxi driver study - research support

• Procedure = Maguire studied brains of London taxis drivers compared to control group of bus driving males

• Findings = experienced male London taxi drivers had larger posterior hippocampi  ( associated with development of spatial and navigational skills ) and higher volume of grey matter in the hippocampus.

• Positive correlation - the longer they’d been driving the taxi’s, the more pronounced the structural brain difference was.

• Conclusion = learning experience of recalling streets and routes altered structure of the drivers brains

How meditation affects plasticity

• Researchers working with Tibetan monks has demonstrated that meditation can change inner workings of brain

• Lutz et al compared 8 practitioners of Tibetan meditation with 10 student volunteers with no previous meditation experience. Both groups fitted with electrical sensors and asked to meditate for short periods.

• Electrodes picked up greater activation of gamma waves in the monks. Students showed only a slight increase in gamma wave activity.

• concluded that meditation can only change working of the brain in short term

Evaluation of plasticity - negative plasticity

May have negative behavioural consequences - evidence has shown brains adaptation to prolonged drug use leads to a poorer cognitive functioning in later life, and increased risk of dementia. This suggests that the brains availing to adapt to damage is not always beneficial

Evaluation of plasticity - research support for age + plasticity

• brain plasticity may be a life long ability.

• Bezzola - 40 hours of golf training produces changes in the neural representations of movement in participants aged 40 - 60. Using fmri the researchers observed reduced motor cortex activity in the novice golfers compared to a control group, suggesting more efficient neural representations after training. This shows that neural plasticity can continue through the lifespan.

Research support for functional recovery

Kempermann et al (1988)

    •    Suggested that an enriched environment could alter the number of neurons in the brain

    •    Found evidence for increase number of neurons in the brain of the rats housed in the complex environment compared the ones in cages.

    •    The housed ones shoed increase in neurons in the hippocampus, brain associated with the formation of new memories and the ability to navigate from one location from another

    •    Clear evidence of the brains ability to change as a result of experience

What happens in the brain during recovery

forming new synaptic connections close to the area of damage

Axonal sprouting

• the growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways

 

Recruitment of homologous areas

Usign area on the opposite side of the brain. This means that specific tasks can still be performed. E.g. if Broca's area was damaged on the left side of the brain, the right sided equivalent might carry out its function.

Synaptic pruning

the brains natural process of eliminating weaker or unnecessary synaptic connections to enhance neural efficiency and cognitive function

Stem cells

• Unspecialised cells that have potential to give rise to different cell types that carry different functions

• Provides treatment for brain damage

• They can directly replace dead sells or secrete growth to rescue injured cells

Neuronal unmasking

• Dormant synapses in the brain become unmasked when there in damage to surrounding area. Opens connections to regions of the brain that are not normally activated

• Result is development of new structures

 

Evaluation of functional recovery - age differences

functional plasticity reduces with age as capacity for neural reorganisation is much better in children than in adults and so adults require more extended practise in order to produce changes after dramatic brain injury and develop compensatory strategies.

Evaluation of functional recovery - educational differences

research shows that patients with equivalent of a college education are 7 times more likely than those who didn’t finish high school to be disability free one year after a moderate to severe traumatic brain injury. More time spent in education improves chances of functional recovery due to improved cognitive reserve

Evaluation of functional recovery - real world application

has contributed to the field of neurorehabilitation by understanding that axonal growth Is possible, encouraging new therapies to be tried. E.g. constraint induced movement therapy is used with stroke patients by repeatedly practicing using the affected part of their body while the unaffected arm is restrained.