Plasticity/Functional recovery Flashcards
What is plasticity?
the brains tendency to change/adapt because of experience and new learning
What happens as we gain new experiences
nerve pathways used frequently develop stronger connections and neurones that are rarely used die.
What is synaptic pruning?
we constantly develop new connections and prune(delete) away weak ones
What is an advantage is synaptic pruning?
enables lifelong plasticity
What was the aim of Maguires study?
to investigate whether change in the brain could be detected because of extensive experience of spatial navigation
What was the method of Maguire’s study?
- 16 male London taxi drivers and 50 non taxi drivers
Used MRI to calculate amount of grey matter in brains of taxi drivers and the control
What were the findings of Maguire’s study?
The posterior hippocampus of taxi drivers was larger than control
The volume of the hippocampus was +vely correlated with amount of time spent as a taxi driver?
- this is the part of the brain associated with navigational skills
What was the conclusion of Maguires study?
the brain changes physically because of experience
What is a strength of Maguires study
MRI is highly empirical
Evaluate empirical as strength of Maguires study?
- highly empirical
- brain scans provide objective evidence to show that cab drivers have a significantly greater volume of grey matter than the control
- strength as it provides verifiable evidence for brain plasticity. suggests conclusions drawn are valid
What are limitations of Maguires study?
- low population validity
- correlational
Evaluate low population validity as a limitation of Maguires study?
- used a small sample of 16 taxi drivers
- not representative of the population which they were drawn from
- So Maguires conclusion that the brain changes physically as a result of experience may not be valid. However there’s no evidence to suggest that a lack of population validity is an issue in this case. Sample only consisted of males so findings arent applicable to females
Evaluate correlational evidence as a limitation of Maguires study?
- His evidence is only correlational
- So its not proven that taxi drivers brains have changed as a direct result of their experience
- however the correlation between their occupation and enhanced grey matter was clear which suggests despite only being correlational his evidence is still valid
What are strengths of Plasicity
Supporting evidence
Evaluate supporting evidence as a strength of Plasticity
- theres evidence to support the claim that plasticity doesnt decline with age
- Ladina Bezzola et al demonstrated how 40 hours of golf training produced changes in neural representations of movement in ppts aged 40-60. Using MRIs they observed increased motor cortex activity in the golfers compared to a control group suggesting more efficient neural representations after changing
- this demonstrates that neural plasticity can continue throughout the life span
What is a limitation of plasticity
- negative behavioural consequences
Evaluate negative plasticity as a limitation of plasticity
- plasticity may have negative behavioural consequences
- 60-80% of amputees have been know to develop phantom limb syndrome. This is the continued experienced sensations in the missing limb as if it was still there. These sensations are usually painful and unpleasant
- this suggests the brains ability to adapt to damage is not always beneficial
What is functional recovery?
Following damage the brain can transfer functions usually performed by damaged areas to other undamaged areas
(neural plasticity)
- can occur quickly after trauma (spontaneous recovery)
How does functional recovery work?
- the brain forms new synaptic connections close to the area of damage
- secondary neural pathways that are not used to carry out certain functions are activated
What structural changes support functional recovery?
- axonal spouting
- denervation super sensitivity
- recruitment of homologous areas on opposite sides of the brian
What is axonal sprouting
growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways
What is denervation of super sensitivity
when axons that do a similar job get aroused to a higher level to compensate for the ones lost
- could have negative consequences of oversensitivity
What is recruitment of homologous areas on opposite sides of the brain
this means specific tasks can still be formed
if an area is damaged in in one side of the brain then the other side equivalent will carry out its functions
What was the aim of Danelli et als study into functional recovery?
to investigate whether the brain can functionally recover after trauma by redistributing functions
What was the method of Danellis stufy
EB was operated on at the age of 2 1/2 to remove a large tumour from his left hemisphere. Due to the size of the tumour almost the entirety of his left hemisphere was removed. His linguistic abilities disappeared and he went thru a longer rehabilitation programme to recover his skills
What were the results of Danellis study
EB’s language abilities started to improve at the age of 5. When tested again at 17 compared to normal controls his right hemisphere compensated for the left. However some areas in the brain were not the expected standard such as minor grammatical erros and a lack of speed
What was the conclusion of Danellis study
Concluded that hemispheric lateralisation can be compensates for to at least a basic degree by the non specialist hemisphere
What is a limitaion of Danellis study?
It is a case study. These are unrepresentative of the population as they are ideologic. We dont know if recovery demonstrated by EB happens in all humans
What is a strength of functional recovery?
practical applications
Evaluate practical applications as a strength of functional recovery
- contributed to the field of neurorehabilitation
- following injury to the brain spontaneous recovery tends to slow down after a few weeks so forms of physical therapy may be required to maintain improvements
- success of such therapies suggests the theory is valid. Also shows research into functional recovery is useful because it helps medical professionals know when interventions are needed
What is a limitation of functional recovery?
Cognitive reserve
Evaluate cognitive reserve as a limitation of functional recovery
- level of a person’s educational attainment may influence how well the brain functionally adapts after injury
- Study discovered that the more time brain injury patients spent in education the greater chances of disability free recovery. those who had more that 16 years of education achieved DFR
- limitation as it implies people with brain damage who have less cognitive reserve are less likely to achieve full recovery. This suggests there are individuals differences in the success of functional recovery
Evaluate age in relation to functional recovery?
- function recovery reduces with age. According to this the only option following traumatic brain injury beyond childhood is to develop compensatory behavioural strategies that work around the deficit
- however studies have suggested that even abilities commonly thought to be fixed in childhood can still be modified in adults with intense retraining
- despite these indications of adult plasticity Elbert et al conclude that the capacity for neural reorganisation is much greater in childhood and adults
What is spontaneous
Functional recovery happens quickly after trauma then slows down after several weeks
