Biopsychology : Plasticity & Functional Recovery

Question 1

What does plasticity mean?

Answer 1

Means that it can change and adapt over time from experiences and new learning.

Question 2

How had the view on plasticity changed?

Answer 2

It was first thought that these changes were only in the developing childhood brain and the adult brain would remain fixed in function and structure, due to having moved beyond a critical period. Research shows that the brain continues to create neural pathways and alter existing one in response to changing experiences.

Question 3

What research is there into plasticity?

Answer 3

Research shows that enriched and impoverish environments can affect the physical structure of the brain…
→ Romanian orphanages
→ Davidson et al (2004) Monk gamma
→ Rosenweig et al (1972) enriched rats
→ Boyke et al (2008) decline w age
→ Draganski et al (2006) exams
→ Mechelli et al (2006) bilingual

Question 4

What did Davidson et al (2004) study?

Answer 4

Found that Tibetan monks had increased gamma waves (coordinate neuronal activity) when meditating, showing long term changes

Question 5

What did Rosenweig et al (1972) study?

Answer 5

found that the brains of highly enriched rats had considerably larger neurons and heavier and thicker cerebral cortex’s version impoverished rats

Question 6

What did Boyke et al (2008) study?

Answer 6

found there is a natural decline in cognitive functioning with age. He found that 60 y.o’s had increased grey matter in the visual cortex when learning to juggle and it decreased when they stopped

Question 7

What did Draganski et al (2006) study?

Answer 7

imaged the brains of medical students 3 months before and after their final exams. Learning-induced changes were seen in the posterior hippocampus and the parietal cortex, presumably as a result of studying for exams.

Question 8

What did Mechelli et al (2006) study?

Answer 8

found a larger parietal cortex in the brains of people who were bilingual vs matched monolingual controls

Question 9

Maguire et al (2000) - overview

Answer 9

studied the brain of London taxi drivers and found significantly more volume of grey matter in the posterior hippocampus than in a matched control group. This part of the brain is associated with the development of spatial and navigation skills in humans and other animals. The spatial learning of the taxi drivers ‘Knowledge’ test (recall of city streets and possible routes) alters the structure of the taxi drivers’ brains.

Question 10

Maguire et al (2000) - Aim

Answer 10

To investigate…

Question 11

Maguire et al (2000) - Procedure

Answer 11

16 healthy right-handed males who were licensed taxi drivers were compared to 50 healthy, right-handed non taxi diver males. An MRI was used to detect changed in the structure of the brain as a result of their experience.

Question 12

Maguire et al (2000) - Findings

Answer 12

the taxi drivers had a larger posterior hippocampus compared to the controls and the controls hand a larger anterior hippocampus.

Question 13

Maguire et al (2000) - Conclusion

Answer 13

Correlations are not causal but it implies that it is the experience of being a taxi driver that changes the brain (at least in the hippocampus).

Question 14

What’s functional recovery?

Answer 14

A form of plasticity where after damage from trauma, the brain is able to redistribute functions normally performed by now damaged areas to undamaged areas.

Question 15

Mechanisms in which a change can occur - Neural reorganisaton

Answer 15

Healthy brain areas may take over the functions of those areas that are damaged, destroyed or even missing (neural re-organisation). → recruitment of homologous areas is when a homologous (similar) area of the brain on the opposite side is used to perform a specific task.

Question 16

Mechanisms in which a change can occur - Neural regeneration

Answer 16

The brain is able to rewire and reorganise itself by forming new neurons (neurogenesis) and/or synaptic connections near to the area of damage. Secondary neural pathways that would not normally be used for certain functions would be activated to enable the functioning to occur in the same way as before.

Question 17

Mechanisms in which a change can occur - Structural changes

Answer 17

Atonal sprouting – growth of new nerve endings which connect with other undamaged nerve cells to form new neural pathways
Reformation of blood vessels
Denervation super sensitivity – axons become more responsive to compensate for the loss of adjacent neurons

Question 18

What are the strengths of plasticity and functional recovery?

Answer 18

• Empirical evidence that provides strong evidence that the brain can undergo structural changes in response to environment demands → Maguire et al (2000) used MRI scans on London taxi drivers and found that their posterior hippocampus culture was significantly larger than the control croup, correlating with the length of time spent as a taxi driver. This supports the concept or neuroplasticity as it shows the hippocampus can increase in size due to the demands placed.

• Supportive evidence showing the brain remains capable of reorganisation throughout adulthood too → Bezzola et al. (2012) demonstrated that 40 hours of golf training resulted in changes in neural activity in individuals aged 40-60. Using fMRI scans, the researchers found reduced motor cortex activity in novice golfers compared to a control group. This indicated that even in later life, the brain can adapt to new experiences and learning.

• Supporting evidence that the brain can undergo significant functional recovery through neuroplasticity, even after severe trauma such a hemispherectomy → Danelli et al. (2013) reported a boy who went under a hemispherectomy at aged 2, resulting in the removal of his entire left hemisphere (responsible for language). By age 17, EB had developed near-normal language abilities, with his right hemisphere compensating for the less. This case demonstrates the brain’s extraordinary capacity to reorganise itself and assume new functions, even in areas not typically associated with those functions.

• Empiracle evidence that shows how the brain can change its structure in response to environmental stimuli → Rosenzweig et al (1972) placed rats in either impoverished or enriched cages for 30-60 days. They found that the rats in enriched environments developed heavier and thicker brain cortex with the frontal lobes being heavier and showing more acetylcholine receptors. Although there are problems with extrapolation.

Question 19

What are the limitations of plasticity and functional recovery?

Answer 19

• The brain’s ability to recover from injury is due to age → Plata et al. (2008) conducted a study investigating the impact of age on recovery from traumatic brain injury (TBI). Their findings found that younger patients had a higher likelihood of achieving a better recovery compared to older adults. The brains exhibit more robust neuroplasticity, allowing for more effective reorganisation and comprehension for lost functions – highlighting the concept of cognitive reserve which tends to be higher in younger individuals due to greater neuroplasticity.

• Individual differences as there’s evidence suggesting women experience better recovery outcomes vs men → Ratcliffe et al (2007) conducted a study examining the differences in functional recovery after brain injury between men and women. They found that women tended to have better outcomes in terms on functional recovery assumed to be due to hormonal differences that enhance neuroplasticity (oestrogen may play a protective role in the brain and facilitate recovery after injury.

• Better recovery with cognitive reserve → Schneider et al (2014) found that brain injury patients with more time spent in education had a higher chance of achieving a disability free recovery (DFR) – 39% over 16 years of education achieved DFR vs 10% with less than 12 years. These findings suggest those with more years of education possess a higher level of “cognitive reserve”, allowing them to recover more efficiently by creating new neural pathways.

• Negative outcomes → Medina et al (2007) found hat prolonged drug use van rust in poorer cognitive functions and increased risk of dementia. Additionally, 60-80% of amputees experience phantom limb syndrome. These examples illustrate that neuroplastciity can contribute to the development of maladaptive behaviours or conditions – the brains capacity to recognise itself in response to negative experiences can lead to detrimental and lasting effects on the individuals mental health and cognitive function.