Plasticity & Functional Recovery of the Brain After Trauma

Question 1

Define ‘plasticity’

Answer 1

• Describes the brain’s tendency to change & adapt (re-wire) as a result of experience & new learning
• Generally involves growth of new connections

Question 2

What are some of the benefits of plasticity?

Answer 2

• Recovery from brain events like strokes,recovery from traumatic brain injuries
• Ability to rewire functions in the brain (e.g., if an area that controls one sense is damaged, other areas may be able to pick up the slack);
• Losing function in one area may enhance functions in other areas (e.g., if one sense is lost, the others may become heightened);

Question 3

What research into plasticity was carried out by Eleanor Maguire et al (2000)?

Answer 3

• Studied the brains of london taxi drivers
• Found significantlly more volume of grey matter in prosterior hippocampus than in a matched control group
• This part of brain is associated w developement of spatial & navigational skills
• As part of their training London cabbies must take a complex test called ‘the knowlege’ which assesses their recall of city streets & possible routes

Question 4

What were Eleanor Maguire’s findings?

Answer 4

• Found that the learning experience of ‘the knowlege’ alters the structure of taxi drivers brains
• Also found the longer the taxi drivers had been in the job the more pronounced the structual difference was (a positive correlation)

Question 5

Give another study with a similar finding to support Eleanor Maguire’s study.

Answer 5

Similar finding was observed by Draganski et al (2006)
* Imaged the brains of medical students 3 months before & after their final exams
* Learning induced changes were seen to have occurred in the prosterior hippocampus & the parietal cortex presumably as a result of learning

Question 6

What was Davidson’s study supporting plasticity of the brain?

Answer 6

Meditation:
* Meditation can beneficially change the inner workings & circuitry of the brain
* Pre-frontal cortex was far more active than non-meditating controls
* Brains of buddhist monks ‘re-organised’, which means they feel a sense of ‘oneness’ with the world around them
* Brainwave patterns of buddhist monks were far more powerful- implying higher level of internal & external thought
* Buddhist monks brains werephysically and functionally superiorthan those without meditation experience.
* Researchers believe that meditationchanges the brainin the same way exercise changes the body.

Question 7

What is functional recovery?

Answer 7

• A form of plasticity
• Following damage through trauma, the brains ability to redistribute or transfer functions usually performed by a damaged area (s) to other undamaged area (s)

Question 8

How long does functional recover take?

Answer 8

Neuroscientists suggest that this process can occur quickly after trauma (spontaneous recovery) & then slow down after several weeks or months

Question 9

What supporting study was done for functional recovery?

Answer 9

Taijiri et al (2013)
* Found that stem cells provided to rats after brain trauma showed a clear development of neuron-like cells in area of injury

This demonstrates the ability of the brain to create new connections using neurons manufactured by stem cells

Question 10

What 3 factors affect functional recovery?

Answer 10

• Age
• Gender
• Treatment/Intervention

Question 11

How does gender affect functional recovery?

Answer 11

Evidence suggests that women recover better from brain injury because their function is not as lateralised (concentrated in one hemisphere)

Question 12

How does age affect functional recovery?

Answer 12

Elbert et al concluded concluded that the capacity for neural reorganisation is much greater in children than in adults

Meaning that neural regeneration is less effective in older brains

Question 13

What structural processes happen during functional recovery?

Answer 13

• Axonal sprouting
• Denervation supersensitivity
• Recruitment of homologous (similar) areas on opposite side of brain

Question 14

What is axonal sprouting?

Answer 14

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

Question 15

What is denervation supersensitivity?

Answer 15

• This occurs when axons that do a similar job become aroused to a higher level to compensate for the ones that are lost

However, it can have the unfortunate consequence of oversensitivity to messages such as pain

Question 16

What is recruitment of homologous areas on opposite side of the brain?

Answer 16

This means that specific tasks can still be performed

e.g. if brocas area was damaged on left side of brain, the right side equivalent would carry out its functions- after period of time functionality may shift to the left side

Question 17

Whats one strength of brain plasticity?

Answer 17

• It does not always decline sharply with age

Plasticity reduces w age however, Ladina Bezzola et al (2012) demonstrated how 40 hours

Question 18

Whats one limitation of plasticity?

Answer 18

• It 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 increased risk of dementia
• 60-80% of amputees have been known to develop phantomom limb syndrome- continued experience of sensations in missing limb as if it were still there.

Suggests that the brains ability to adapt to damage is not always beneficial

Question 19

Give one strength of functional recovery?

Answer 19

It’s real world application
* Understanding processes involved in plasticity has contributed to the field of neurorehabiliaton
* Simply understanding that axonal growth is possible encourages new therapies to be tried

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

Question 20

Give one limitation of functional recovery.

Answer 20

• Level of education may influence recovery rates
• Schneider et al - revealed more time people with brain injury had spent in education- taken as an indication of cognitive reserve the greater their chances of a disability free recovery

Imply that people with brain damage who have insufficient DFR are less likely to achieve a full recovery