plasticty and fucntional recovery of the brain after trauma

Question 1

Plasticity - brain plasticity

Answer 1

ability to change throughout life

during infancy the brain experiences a rapid growth in the number of synaptic connections it has

peaking at about 15000 per neuron at 2-3 years - Gopnick et al

Twice as many as the adult brain

as we age rarely sued connections are deleted

frequently used connections are strengthened - called synaptic pruning

syanptic pruning enables lifelong plasticity where new neural connections are formed in response to new demands on the brain

Question 2

plasticity - research into plasticity

Answer 2

Maguire et al

studied the brains of london taxi drivers and found significantly more volume of grey matter in the posterior hippocampus than in the 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 test

assesses their recall of their recall of the city streets and possible routes

Maguire found that this learning experiences alters the structure of the taxi drivers brains

also found that the longer the taxi drivers have been in the job the more pronounced was the structural difference (positive correlation)

Question 3

limitation

Answer 3

Negative plasticity

plasticity may have negative behavioural consequences

evidence has shown that the brains adaption to prolonged drug use leads to poorer cognitive functioning in later life

as well as an increased risk of dementia (medina et al)

60-80% of amputees have been known to develop phantom limb syndrome

theses sensations are usually unpleasant, painful and are thought to be due to cortical reorganisation in the somatosensory coretex that occurs as a result of limb loss

this suggests that the brains ability to adapt to damage is not always beneficial

Question 4

strength

Answer 4

age and plasticity

brain plasticity may be a life-long ability

In general plasticity rescued with age

Bezzola demonstrated how 40 hours og golf training produced changes in the neural representations of movement in participants aged 40-60

Using fMRI the researchers observed increased motor cortex activity in the novice golfers compared to a control group

suggesting more efficient neural respresentaitons after training

shows that neural plasticity can continue throughout the lifespan

Question 5

functional recovery - after brain trauma

Answer 5

following physical injury or other forms of trauma such as the experience of a stroke unaffected areas of the brain are often ab,e to adapt and compensate for those areas that are damaged

Functional recovery that may occur in the brain after trauma is an 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 (spontaneous recovery) and then slow down after several weeks or months

At this point the individual may require rehabilitative therapy to further their recovery

Question 6

functional recovery - what happens in the brain during recovery

Answer 6

brain is able to rewire and reorganise itself by forming new synaptic connections close to the area of damage

secondary neural pathways that would not typically be used to carry out certain functions are activated to enable functioning to continue , often in the same way as before

Question 7

functional recovery - structural changes

Answer 7

axonal sprouting - the growth of new nerve endings which connect with other unmanaged nerve cells to form new neuronal pathways

Denervation supersentivity- this occurs when axons that do a similar job become aroused to a higher level to compensate for the ones that are lost
yet can have the negative consequence of oversentivity to messages such as pain

recruitment of homologous - similar areas on the opposite side of the brain
means that specific task can stilll be performed
an example - if the broca’s area was damaged on the left aide of the brain the right sided equivalent would carry out its functions
after a period of time functionality may then shift back on to the left side

Question 8

strength

Answer 8

real world application

understanding the processes involved in plasticity has contributed to to the field of nero rehabilitation

understanding that axonal growth is possible encourages new therapies to be tried

for example - constraint-indicted movement therapy is used with stoke patients whereby they repeatedly practice using the affected part of the body while the unaffected arm is restrained

shows that research into functional recovery is useful as it helps medical professionals know when interventions need to be made

Question 9

limitation

Answer 9

cognitive reserve

level of education may influence recovery rates

Schneider revelead that the more time people with a brain injury had spent in education the greater their chances of a having a disability free recovery DFR

40% of those who archived DFR has more than 16 years of education

10% of those who has less than 12 years of education

this would imply that people with brain damage who have insufficient DFR are less likely to achieve full recovery