Brain plasticity and functional recovery

Question 1

Outline brain plasticity + research

Answer 1

New synapses are formed between neurons due to experience and learning
This peaks at around 15,000 at age 2-3
At any time in life existing neural connections can change

Synaptic pruning - As we age, rarely used connections are eliminated. Frequently used connections are strengthened and become more specialised.

McGuire studied London taxi drivers and found:

• Increased grey matter was found in the brains of taxi drivers compared with controls in the posterior (rear) hippocampus
• A positive correlation was found between the amount of time spent as a taxi driver and volume in the right posterior hippocampus

Question 2

Evaluate.

Answer 2

+ Bezzola et al used fMRI scans to study novice golfers (aged 40-60 years) who took part in 40 hours training. They found increased motor cortex activity in the novice golfers compared to a control group
- However, brain plasticity can have negative consequences. 60-80% of amputees suffer phantom limb syndrome. These feelings are problematic for the patient and have been linked back to cortical reorganisation in the somatosensory cortex.

+ Brain scans of medical students 3 months before and after their exams show an increase in the posterior hippocampus due to learning.

+Research suggests there may be seasonal plasticity in the brain in response to environmental changes for example suprachiasmatic nucleus (SCN) regulates sleep wake cycle shrinks in all animals throughout spring and expands in autumn.
-Counterpoint: Unable to generalise to humans.

Question 3

Outline functional recovery.

Answer 3

If a person has a brain injury or trauma e.g. a stroke functional recovery occurs which is an example of neuroplasticity.

Axonal sprouting leads to growth of new nerve endings which connect with other undamaged nerve cells to form new neural pathways. Denervation super sensitivity occurs so the brain adapts and transfers functions to undamaged areas.

This process can occur quickly after trauma (functional recovery) and then slow down after several weeks or months. At this point the individual may need rehabilitative therapy. e.g. physiotherapy or speech and language therapy

Question 4

Evaluate.

Answer 4

+ real world application: neurorehabilitation can be used with stroke patients

• Counterpoint: level of level of education has been found to affect recovery rates - 40% of people who achieved disability free recovery (DFR) had more than 16 years’ education whereas 10% had less than 12 years in education.

+ stem cells provided to total rats after brain trauma showed a clear development of neuron-like cells in the area of injury.

• Capacity for neural reorganisation is much greater in children than in adults, meaning that neural regeneration is less effective with age.