Plasticity and functional recovery

Define plasticity

the brain’s tendency to change and adapt (functionally and physically) as a result of experiences and new learning

What is synaptic pruning?

weakening of unused connections; strengthening of used ones

Who did Maguire study in relation to brain plasticity?

taxi drivers

What did Maguire find?

significantly larger volume of grey matter in the posterior hippocampus than in a matched control group)

What were the groups matched on?

age, gender and dominant hand

What is the hippocampus associated with?

spatial/navigational skills in humans and other animals

Why did Maguire argue that the structure of a taxi driver’s brain changes?

as being one requires complex learning and testing, they are expected to recall city streets and routes.

How did Maguire counter the argument that taxi drivers could have become taxi drivers because they have a large hippocampus?

the longer the taxi driver had been in the job, the more pronounced the structural difference - positive correlation

Define functional recovery

a type of plasticity where after trauma, the brain redistributes functions from damaged areas to other undamaged areas

healthy brain areas may take over the functions that are affected or lost completely

How long after trauma does functional recovery happen?

quickly (spontaneous recovery) but then slows down after a few weeks/months. Therapy may then be required.

functional recovery is a more efficient process in younger people

Who is Jody Miller?

A girl who had her entire right hemisphere removed (hemispherectomy) to stop severe seizures

Why did she need the right hemisphere removed?

She had life-threatening, uncontrollable epileptic seizures

What happened after the surgery?

She was able to walk within days and returned to normal life remarkably quickly

Why is this case important for psychology?

It provides strong evidence for brain plasticity and functional recovery

What structural changes take place in the brain for secondary neuron pathways that are nor typically used to be activated enabling functioning to continue in the same way as before

1. axonal sprouting

2. neuronal unmasking

3. denervation super sensitivity

4. recruitment of homologous areas

What is axonal sprouting?

the formation of new synaptic connections close to the area of damage

What is neuronal unmasking?

secondary neuronal pathways that aren’t typically used (dormant) become activated to recover a lost connection

What is denervation super sensitivity?

axons that do a similar job to the connections that were lost become further aroused to compensate for the lost one. This can lead to oversensitivity of messages

What is recruitment of homologous areas?

the lost functions are recovered by the same area on the opposite side of the brain. If Broca’s area was damaged, functioning may be recovered by the frontal lobe in the right hemisphere

Give some factors that affect recovery.

Age, therapy, extent of damage, time since injury

How is the fact that research into functional recovery has led to effective, real-world rehabilitation methods for people recovering from brain damage a strength?

this demonstrates how understanding plasticity has produced evidence-based treatments that help patients regain motor, cognitive and emotional functions. It highlights the positive impact of understanding neural plasticity on individuals’ lives, wider society, and even the economy.

Give an example of this strength.

for example, Taub et al. (2013) studied rehabilitation programmes, such as constraint-induced movement therapy, where the unaffected arm is restricted to force use of the affected one. They found that patients receiving this therapy improved the functional use of their affected arm more than those doing standard exercises, showing that targeting undamaged brain areas can encourage new neural connections.

How is the fact that there is research evidence support for experiences affecting the physical structure a strength of plasticity?

because it demonstrates that the brain can physically adapt in response to new experiences, supporting the idea that plasticity is an active, ongoing process rather than something that is fixed. The fact that measurable changes were found provides strong scientific, objective evidence increasing the validity.

Give an example of this strength.

for example, Lazor et al (2005) used MRI scans to investigate the cortex thickness in mediators vs non-mediators. Individuals who took part in an 8-week mindfulness course showed an increase in grey matter in areas linked to attention and sensory processing in comparison to individuals who didn’t take part in the mindfulness course

How is the fact that the psychological research in the area of plasticity and functional recovery can be considered scientific a strength?

because the use of scientific, objective methods increases the validity of the findings. These scans are highly reliable and allow researchers to measure brain structures accurately

Give an example of this strength

for instance, Maguire’s study of the London taxi drivers utilised brain scans in order to investigate the differences of the taxi driver vs control groups brain. Not only this, but ppts were matched for age, gender and dominant hand

How is the fact that plasticity and functional recovery supporting research utilises animals a weakness? (+counter/development)

because whilst this does provide evidence for plasticity, research of this nature should be applie with caution using animals raises problems with generalising the findings to humans. It is also unethical what was done in this particular animal study

C: however, the good thing about animal studies is that it provides opportunities for highly controlled research that would be unethical or impossible to conduct on humans

Give an example of this weakness

for example, Wiesel (1963) sewed one eye of a kitten shut to see what would happen to the visual area liked to that eye. They found that the visual cortex remained active as it was still processing information from the other eye