Outline and Evaluate the Evidence for Plasticity and Functional Recovery PDF

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essay based on evaluating evidence for plasticity and functional recovery...

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Outline and Evaluate the Evidence for Plasticity and Functional Recovery The brain can change and adapt through life. In infancy the brain has around 2500 synaptic connections, but this peaks at 2-3 years old, where you have about 15000. In adult brains this is lower, with about 7500. Recent research suggests that at any time during life, existing neural connections can change, or new neural connections can be formed because of learning and experience. This is called synaptic bridging. Similarly, when they are lost, this is synaptic pruning. Maguire studied the brains of London taxi drivers and found that they had a significantly higher level of grey matter in the hippocampus. This is associated with the development of spatial and navigational skills. As part of training, the taxi drivers would take a test of recall of the streets and possible routes. This alters the structure of the brain. The longer they had the job, the more pronounced the structure was. Similarly, Draganski showed that extensive learning of abstract information can trigger changes in the brain. He imaged the brains of German medical students 3 months before their final exams, and 3 months after. He compared this to students not studying the exam at that time. He found that the learning induced changes in the hippocampus and parietal cortex. This shows the brain formed more synaptic connections, supporting the idea that bridging can occur throughout life, and the plasticity of the brain. Functional recovery is the ability of the brain to transfer the functions of areas, damaged through trauma, to healthy areas of the brain, allowing for normal functioning. For example, Jodi Miller has her left hemisphere removed, and neuroplasticity allowed her to use her right bodily functions, using cerebral spinal fluid. An advantage for plasticity is the evidence form animal studies. Hubel and Wiesel sewed one eye of a kitten shut and analysed the brain’s cortical responses. They found that the area of the visual cortex, associated with the shut eye, was not idle, but continued to process information from the open eye. This is an important piece of support for plasticity as it shows the brain can change to compensate for damaged areas. However, there is a question regarding extrapolation, as the results may not be generalisable to humans. One strength of plasticity is the practical application of neurorehabilitation. Following illness or injury to the brain, recovery slows down after several weeks. Therefore, physical therapy may be required to maintain improvements in functioning e.g. movement therapy, electrical stimulation. This matters because, whilst it shows the brain can only fix itself up to a certain point, it has led to the development of therapies and interventions to ensure that functional recovery is always completely successful. This implies that although nature plays a big role in recovery, it must work with environmental factors in order to fully compensate for damage. However, rewiring itself can have maladaptive consequences. For example, Ramachandran and Hirstein found that 60-80% of amputees have developed phantom limb syndrome. These feelings are problematic for the patient and have been linked back to cortical reorganisation in the somatosensory cortex. This suggests that the brain may rewire itself incorrectly sometimes. This suggests the ideas cannot apply fully to every individual, as the brain does not respond to damage in the same way, each time. This has possible negative implications for those it represents, as they may be shown to be fully recovered, when they are not. Functional recovery also has its limits, as the brain can only repair itself up to a certain point, after which therapy is required. Lieperta found that after constraint induced movement therapy, the motor performance of stroke patients improved significantly. This shows functional recovery cannot be relied on to reinstate normal function. This further supports the importance of nature and nurture working together, to improve the lives of those with brain damage, and suggests the explanation for plasticity is only applicable to some patients....