Plasticity and Functional Recovery of the Brain After Trauma

Plasticity: This describes the brain’s tendency to change and adapt as a result of experience and new learning. This generally involves the growth of new connections.

Synaptic Pruning: As we age, rarely-used connections are deleted and frequently-used connections are strengthened.

Maguire et al (2000): Studied brains of London taxi drivers that had taken the knowledge and found more volume grey matter in the posterior hippocampus (associated with spatial and navigational skills) than in a matched control group. There was also a positive correlation between time as a taxi driver and amount of matter.

Draganski et al (2006): Imaged the brains of medical students three months before and after their final exams. Learning-induced changes were seen to have occurred in the posterior hippocampus and the parietal cortex presumably as a result of the learning.

Negative Plasticity: Evidence shows prolonged drug use leads to poorer cognitive functioning later in life and 60-80% of amputees have been known to develop phantom limb syndrome thought to be due to cortical reorganisation in the somatosensory cortex that occurs as a result of limb loss.

Age and Plasticity: Bezzola et al (2012) demonstrated how 40 hours of golf-training produced changes in the neural representations of movement in participants aged 40-60. With an fMRI the researchers based increase motor cortex activity in the novice golfers compared to a control group.

Functional Recovery: A form of plasticity. Following damage through trauma, the brain’s ability to redistribute or transfer functions usually performed by a damaged area(s) to other, undamaged area(s).

Brain During Recovery: Secondary neural pathways are activated to enable functioning to continue. This is supported by axonal sprouting, denervation hypersensitivity and recruitment of homologous areas.

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

Denervation Supersensitivity: 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 negative consequence of oversensitivuty such as pain.

Recruitment of Homologous Areas: Areas on the opposite side of the brain that are activated so that specific tasks can still be performed. For example, if the Broca’s area was damaged on the left side then the right side equivalent would carry out its functions. After a time, the functionality may return to the left.

Real-World Application: Understanding processes involved in plasticity has contributed to neurorehabilitation. For example, constraint-induced movement therapy is used with stroke patients whereby they repeatedly practise using the affected part of their body while the unaffected arm is restrained.

Cognitive Reserve: Recovery may be correlational to education. Schneider et al revealed that more time people with a brain injury had spent in education, the greater their chances of a disability-free recovery. 40% with DFS had more than 16 years education compared to 10% of those with less than 12 years.