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Plasticity and Functional Recovery of the Brain after Trauma
Transcript of Plasticity and Functional Recovery of the Brain after Trauma
Maguire et al (2000) - studied London taxi drivers brains and found significantly more grey matter in the posterior hippocampus than in a matched control group.
This part of the brain is associated with the development of spatial and navigational skills in humans and other animals.
As part of their training, London taxi drivers have to learn 'the knowledge'. Learning this seems to change the structure of the taxi drivers brains. Also, the longer they'd been a taxi driver, the more significant the change in the brain.
Draganski et al (2006) imaged the brains of medical students 3 months before and after their final exams. Changes had occured in the posterior hippocampus and the parietal cortex.
Plasticity And Functional Recovery Of The Brain After Trauma
Functional Recovery of the Brain after Trauma
After physical injury, or other forms of trauma (like a stroke) unaffected areas of the brain are often able to adapt and compensate for the areas that are damaged.
The functional recovery that takes place in the brain after trauma is another example of neural plasticity.
Neuroscientists say this process can occur quickly after trauma (spontaneous recovery) and then slow down after several weeks or months. At this point the person may need rehabilitative therapy to further their recovery.
What Happens In The Brain During Recovery?
The brain can rewire and reorganise itself by forming new synaptic connections close to the area of damage.
Secondary neural pathways that would not normally be used to carry out certain functions are activated to enable functioning to continue as it did before (Doidge, 2007).
The process is supported by some structural changes:
growth of new nerve endings which connect with damaged nerve cells to form new pathways
Reformation of blood vessels
Recruitment of homologous (similar) areas on the opposite side of brain
to perform specific tasks i.e if the Broca's area was damaged on the left side then the right sided equivalent would carry out its functions.
Understanding plasticity has helped to develop neurorehabilitation - the physical therapy that's done after spontaneous recovery slows down
The brain's ability to rewire itself can sometimes have negative behavioural consequences e.g prolonged drug use can result in poorer cognitive function as well as an increased risk of dementia.
Also, 60-80% of amputees have been known to develop phantom limb syndrome. These sensations are thought to be due to cortical reorganisation in the somatosensory cortex that occurs as a result of limb loss.
Age and Plasticity:
Functional plasticity tends to reduce with age. However, Bezzola et al (2012) showed that 40 hours of golf training produced changes motor cortex activity in participants aged 40-60 suggesting neural plasticity does continue throughout a lifetime.
Brain appears to be 'plastic' - meaning it has the ability to change throughout life.
Infancy - brain develops a huge amount of
synaptic connections peaking at 15,000 at
age 2-3 (Gopnick et al, 1999). This is twice as
many as there are in the adult brain. As we
age, rarely used connections are deleted
and frequently used connections are
trengthened - this is called synaptic pruning.
It was orginally thought that changes in the brain only happened during childhood and that the adult brain was 'fixed'. However, recent research suggests that neural connections can change at any age or new connections can be made as a result of learning and experience. This is called plasticity.
Meditation and Mindfulness:
Lazar et al (2005) showed that individuals that took part in an 8 week mindfulness stress reduction course showed an increase in grey matter in the left hippocampus (the part of the brain associated with learning and memory)
This suggests that the brain structure is not fixed and can in fact change with learning
Support From Animal Studies:
Early evidence of neuroplasticity came from animal studies. Hubel and Wiesel (1963) sewed one eye of a kitten shut and analysed the brain's cortical responses. They found the area of the visual cortex associated with the shut eye was still active and continued to process information from the open eye.
The Concept of Cognitive Reserve:
Evidence suggests that a person's educational attainment may influence how well the brain functionally adapts after injury.
Schneider et al (2014) discovered that the more time brain injury patients had spent in education (seen as an indication of their 'cognitive reserve'), the greater their chance of disability-free recovery (DFR)