plasticity and functional recovery of the brain after trauma

Question 1

plasticity

Answer 1

the brains tendency to change or adapt because of experience and new learning
- this generally involves the growth of new connections

Question 2

when does growth of synaptic connections peak

Answer 2

at around 2-3

Question 3

what happens to nerve pathways that are used frequently

Answer 3

stronger connections are developed

Question 4

what happens to nerve pathways that are rarely used

Answer 4

they eventually die

Question 5

synaptic pruning

Answer 5

pruning away weak synaptic connections and developing new connections to adapt to a changing environment

Question 6

is plasticity lifelong

Answer 6

yes, synaptic pruning allows for lifelong plasticity where new neural connections are formed in response to new demands on the brain

Question 7

natural decline in cognitive functioning

Answer 7

age means that cognitive functioning naturally declines over time

Question 8

whats the supporting study for plasticity

Answer 8

maguire

Question 9

aim of maguire

Answer 9

To investigate whether changes in the brain could be detected because of
extensive experience of spatial navigation.

Question 10

method of maguire

Answer 10

The sample consisted of 16 male London taxi drivers and 50 males who did
not drive taxis (control group). Using an MRI scanner, the researchers
calculated the amount of grey matter in the brains of taxi drivers and a set
of control participants.

Question 11

findings of maguire

Answer 11

• The first finding was that the posterior hippocampus of taxi
  drivers was significantly larger relative to those of control participants. This part of the brain is associated with spatial and navigational skills in humans and animals.
• The second finding was that the posterior hippocampal volume was positively correlated with the amount of time they had spent as a taxi driver (a measure of the extent of their experience).

Question 12

conclusion of maguires study

Answer 12

The brain changes physically because of experience (plasticity of the brain)

Question 13

MRI scan - empirical

Answer 13

• strength of Maguire’s research is that it is highly empirical.
• Brain scans provide objective evidence to show that the cab drivers she studied did
  indeed have a significantly greater volume of grey matter in the posterior hippocampus
  than did a matched control group.
• This is a strength because these findings provide verifiable evidence for brain plasticity and
  so suggests that the conclusions drawn about brain plasticity are valid.

Question 14

correlational data

Answer 14

• An issue with Maguire’s evidence is that it is only correlational.
• This means that she has not proven that the taxi driver’s brains have changed as a direct result of their experience – it might be due to some other factor.
• However, the correlation between their occupation and enhanced grey matter was very clear which suggests that, despite only being correlational, Maguire’s evidence is valid.

Question 15

low population validity

Answer 15

• An issue with Maguire’s research is that she only used a small sample of 16 male London taxi drivers.
• It is possible that this group of participants is not representative of the population from which they were drawn.
• This means that Maguire’s conclusion that the brain changes physically as a result of
  experience may not be valid. - However, there is no evidence to suggest that her sample was
  unrepresentative which suggests that a lack of population validity is not really an issue in this
  case.
• However, since the sample only consisted of males it is possible that the findings may not be applicable to females.

Question 16

age and plasticity

Answer 16

• There is evidence to support the claim that plasticity does not inevitably decline sharply with
  age.
• Ladina Bezzola et al demonstrated how 40 hours of golf training produced changes in the neural representations of movement in participants aged 40-60. Using fMRI scans,
  researchers observed increased motor cortex activity in the novice golfers compared to a
  control group, suggesting more efficient neural representations after training.
• This demonstrates that neural plasticity can continue throughout the lifespan.

Question 17

functional recovery

Answer 17

a form of plasticity following damage through trauma the brains ability to distribute or transfer functions usually performed by a damaged area to other undamaged areas

Question 18

does functional recovery last

Answer 18

• occurs quickly after trauma (spontaneous recovery)
• slows down after several weeks and rehabilitation therapy may be needed to further recovery

Question 19

what happens to the brain during recovery

Answer 19

• new synaptic connections formed close to the area of damaged
• secondary neuronal pathways that wouldnt normally be used are activated to enable functioning to continue

Question 20

what 3 things happen in the brain

Answer 20

• axonal spouting
• denervation super sensitivity
• recruitment of homologous areas on the opposite side of the brain

Question 21

axonal spouting

Answer 21

the growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways

Question 22

denervation super sensitivity

Answer 22

axons that do a similar job become aroused to a higher level to compensate for the one that are lost

Question 23

what is an issue with denervation super sensitivity

Answer 23

nerves can become oversensitive to messages relating to pain

Question 24

recruitment of homologous areas on the opposite side of the brain

Answer 24

meaning specific tasks can still be performed
- eg if brocas area was damaged on the left side of the brain the right side equivalent may carry out its functions
- functionality may then shift back to the left side

Question 25

what study provides supporting evidence for functional recovery

Answer 25

danelli

Question 26

danelli aim

Answer 26

To investigate if the brain can functionally recover after trauma by redistributing functions normally performed by the damaged area to other undamaged areas.

Question 27

danelli method

Answer 27

EB was operated on at the age of two and a half to remove a large tumour from his left hemisphere. Due to the size of the tumour virtually the entire left hemisphere was removed, and, at the time, all his linguistic abilities disappeared. He then underwent a long rehabilitation programme to recover his language skills.

Question 28

danelli results

Answer 28

His language abilities started to improve at around the age of 5. When tested again at the age of 17 to compare his language abilities with ‘normal’ controls Danelli et.al. found that his right hemisphere had compensated for the loss of the left hemisphere and that he was functioning well linguistically. However, they did find some areas which were not to the expected standard e.g., minor grammatical errors and lack of speed when asked to name objects in pictures.

Question 29

danelli conclusion

Answer 29

They concluded that hemispheric lateralisation can be compensated for to at least a basic degree by the non-specialist hemisphere.

Question 30

case study

Answer 30

P Case studies of individuals are, by their very nature, unrepresentative. This is because there is no certainty that they are typical of the population from which they are drawn. E Consequently, we cannot be certain that the functional brain recovery demonstrated by EB would occur in other human beings – older people in particular. E This study therefore does not prove that functional recovery is possible. L However, there is no evidence to suggest that EB is unrepresentative and hence the study of Danelli et.al. provides reasonable evidence in support of this theory.

Question 31

practical application of functional recovery

Answer 31

P One strength of functional recovery is its real-world application. Understanding the processes involved in plasticity has contributed to the field of neurorehabilitation. E Following illness of injury to the brain spontaneous recovery tends to slow down after a number of weeks so forms of physical therapy (such as electrical stimulation of the brain) may be required in order to maintain improvements in functioning. E The success of such therapies (based as they are on research into plasticity) suggests that the theory, and the research underpinning it, are valid. It also shows that research into functional recovery is useful because it helps medical professionals know when interventions need to be made. L However, it also shows that, even though the brain may have the capacity to ‘fix’ itself to some extent, this process requires further intervention if it is to be completely successful.