plasticity and functional recovery of the brain after trauma Flashcards
What is plasticity?
-the brains tendency to changes and adapt functionally and physically as a result of experience and new learning
What is functional recovery?
- a form of plasticity
- following damage through trauma, the brain’s ability to redistribute or transfer functions usually performed by a damaged area to other undamaged areas
What is brain plasticity?
- the brain would appear to be plastic in the sense that it has the ability to change throughout life
- during infancy, the brain experiences a rapid growth in the number of synaptic connections it has, peaking at approximately 15,000 at age 2-3 years
- this equates to about twice as many as there are in the adult brain
- as we age, rarely used connections are deleted and frequently used connections are strengthened - a process known as synaptic pruning
- it was originally thought that such changes were restricted to the developing brain within childhood and that the adult brain, having moved beyond a critical period, would remain fixed and static in terms of function and structure
- however, more recent research suggests that at any time in life existing neural connections can change, or new neural connections can be formed, as a result of learning and experience
What is research into plasticity?
- Maguire et al studied the brains of London taxi drivers and found significantly more volume of 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 cabbies must take a complex test called ‘the knowledge’ which assesses the recall of the city streets and possible routes
- it appears that the result of this learning experience is to alter the structure of the taxi drivers’ brains
- it is also noteworthy that the longer they had been in the job, the more pronounced was the structural difference showing a positive correlation
- a similar finding was observed by Draganski et al who imaged the brains of medical students three months before and after their final exams
- learning-induced changes were seen to have occurred in the posterior hippocampus and the varietal cortex presumably as a result of the exam
- finally Michelle et al also found a larger varietal cortex presumably as a result of the exam
- finally Michelle et al also found a larger varietal cortex in the brains of people who were bilingual compared to matched monolingual controls
What is functional recovery of the brain after trauma?
- following physical injury or other forms of trauma such as the experience of a stroke, unaffected areas of the brain are often able to adapt and compensate for those areas that are damaged
- the functional recovery that may occur in the brain after trauma is another example of neural plasticity
- healthy brain areas may take over the functions of those areas that are damaged, destroyed or even missing
- neuroscientists suggest that this process can occur quickly after trauma and then slowly done after several weeks or months
- at this point the individual may require rehabilitative therapy to further their recovery
What happens in the brain during recovery?
- the brain is able to rewire and recognise itself by forming new synaptic connections close to the area of the damage a bit like avoiding roadwork on the way to school by finding a different route
- secondary neural pathways that would not typically be used to carry out certain functions are activated or unmasked to enable functioning to continue often in the same way as before
- this proceed is supported by a number of structural changes in the brain including atonal sprouting, reformation of blood vessels and recruitment of homologous areas
What are the evaluation points of plasticity and functional recovery of the rain after trauma?
+practical application - neurorehabilitation and physical therapy e.g. electrical stimulation can be used to maintain recovery
+negative plasticity behavioural consequences: phantom limb syndrome
+evidence: Buddhist monks had more gamma waves due to meditation
+sewing the eye of a kitten closed: the visual cortex for the shut eye was not idle, it processed information from the open eye instead
How does practical application support the plasticity and functional recovery of the brain after trauma?
- understanding the process involved in plasticity has contributed to the field of neuroreabilitation
- following illness or injury to the brain, spontaneous recovery tends to slow down after a number of weeks so forms of physical therapy may be required to maintain improvements in functioning
- techniques may include movement therapy and electrical stimulation of the brain to counter the deficits in motor and/or cognitive functioning that may be experienced following a stroke, for instance
- this shows that, although the brain may have the capacity to fix itself to a point, this process requires further intervention if it is to be completely successful
How does negative plasticity support plasticity and functional recovery of the brain after trauma?
- the brain is able to rewire itself in maladaptive ways such as poor cognitive functioning due to drug use
- phantom limb syndrome in amputees which is unpleasant and painful
How does evidence support plasticity and functional recovery of the brain after trauma?
- Buddhist monks who meditated frequently had a much greater activation of gamma waves than students with no experience of meditation.
- this highlights the idea of plasticity and the brain’s ability to adapt as a result of new experience like mediation.
What is atonal sprouting?
-the growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways
What is recruitment of homologous areas?
- if Broca’s area was damaged in the left side of the brain, the right-side equivalent would carry out its functions
- after a period of time, functionality may then shift back to the left side
How does the case of sewing the eye of a kitten closed support plasticity?
-a cats eye was sewn shut and the brain response was analysed which found the visual cortex associated with the shut eye was not idle but continued to process information from the open eye
