Knowt
BRAIN PLASTICITY & FUNCTIONAL RECOVERY
~BRAIN PLASTICITY~
Pruning → where connections are lost due to lack of use
Bridging → where new connections are created due to use and new stimuli
→ It is believed that the purpose of synaptic pruning is to remove unnecessary neural structures from the brain
→ Simpler associations formed during childhood are thought to be replaced by more complex structures
MAGUIRE ET AL’S STUDY:
AIM:
Aimed to investigate whether the brains of London taxi drivers showed any structural changes due to their extensive experience with navigation, and how this might demonstraste plasticity
PARTICIPANTS:
16 right-handed, male taxi drivers who had been driving for at least 1.5 years
Control group of 50 non-taxi drivers
FINDINGS:
Taxi drivers had a significantly larger posterior hippocampus compared to control grous (hippocampus is involved in spatial memory and navigation)
Taxi drivers exhibited greater grey matter in the hippocampus (associated with processing information)
Increase in hippocampal volume that’s positively correlated with the number of years spent as a taxi driver
CONCLUSION:
Study supports the concept of brain plasticity, by showing that the brain changes in response to environmental demands
Structural changes in the hippocampus indicate that prolonged experience in navigation leads to the development of new neural connections
~FUNCTIONAL RECOVERY~
→ Another example of plasticity is the way the brain can adapt after trauma
→ The brain does this through neuronal unmasking where ‘dormant’ synapses open connections to compensate for the nearby damaged area of the brain
→ This allows new connections in the brain to be activated, thus recovering any damage occurring in specific regions
→ Scientists believe the recovery process occurs quickly after trauma (spontaneous recovery) and then slows down after several weeks/months
Axonal Sprouting → the growth of new nerve endings which connect with other undamaged nerve cells to form new neural pathways
Denervation Supersensitivity → this occurs when axons that do a similar job become a doused to a higher level to compensate for the ones that are lost. However, it can have the negative consequence of oversensitivity to messages such as pain
Recruitment of homologous areas on the opposite side of the brain → this means that specific tasks can still be performed
EVALUATION
Research Support
→ LIFE-LONG ABILITY
One strength is that brain plasticity may be a life-long ability.
In general, plasticity reduces with age. However, Bezzola et al (2012) demonstrated how 40 hours of golf training produced changes in the neural representations of movement in participants aged 40-60.
Using fMRI, the researchers observed increased motor cortex activity in the novice golfers, compared to a control group, suggesting more efficient neural representations after training.
This shows that neutral plasticity can continue throughout the lifespan.
→ REAL-WORLD APPLICATION
One strength of functional recovery research is its real-world application.
Understanding the processes involved in plasticity has contributed to the field of neuro rehabilitation. Simply understanding that afinal growth is possible encourages new therapies to be tried.
For example, constraint/induced movement therapy is used with stroke patients whereby they repeatedly practice using the affected part of their body, while the unaffected arm is restrained.
This shows that research into functional recovery is useful as it helps medical professionals know when interventions need to be made.
Conflicting Evidence
→ CONFOUNDING VARIABLES
One limitation of functional recovery is that the level of education may influence recovery rates.
Schneider et al (2014) revealed that the more time people with a brain injury had spent in education - taken as an indication of their ‘cognitive reserve’ - the greater their chances of a disability-free recovery (DFR).
40% of those who achieved DFR had more than 16 years’ education compared to about 10% of those who had less than 12 years’ education.
This would imply that people with brain damage who have insufficient DFR are less likely to achieve a full recovery.
→ NEGATIVE BEHAVIOURAL CONSEQUENCES
Another limitation of plasticity is that it may have negative behavioural consequences.
60-80% of amputees have been known to develop phantom limb syndrome - the continued experience lf sensations in the missing limb as if it were still there.
These sensations are usually unpleasant, painful and are thought to be due to cortical reorganisation in the somatosensory cortex that occurs as a result of limb loss.
