Plasticity and Functional Recovery after Trauma

Question 1

What is Plasticity

Answer 1

The idea that the brain has the ability to change throughout life
As we get older synaptic connections that we don’t use are deleted, and those that we use frequently are strengthened (synaptic pruning)
Age has a negative correlation with plasticity (as age increases, plasticity decreases)
more recent research suggest that at any time in life existing neural connections can change or new neural connections can be formed as a result of learning and experience

Question 2

Maguire et al (2000)

Answer 2

Studied the brains of London taxi drivers
Found more grey matter in the posterior hippocampus (associated with navigational skills) than in a matched control group
Concluded that learning is altering the structure of the taxi drivers brains as the longer they’ve been in the job the more pronounced the structure difference was (positive correlation)

Question 3

Draganski et al (2006)

Answer 3

Imaged the brains of medical students three months before and three months after their final exams
Found there were changes in the posterior hippocampus and the paretial cortex
This was thought to be as a result of learning for the final exam

Question 4

Mechelli et al (2004)

Answer 4

Found a larger paretial cortex in the brains of people who were bilingual compared to matched monolingual controls

Question 5

What is Functional Recovery

Answer 5

When healthy brain areas take over the functions of those areas that are damaged, destroyed or missing
This can happen quickly after trauma (spontaneous recovery)
Recovery may then slow down and require a patient to have rehabilitative therapy to aid recovery

Question 6

How does the Brain Recover

Answer 6

1) The brain forms new synaptic connections close to the area of damage
2) Secondary neural pathways that are not normally used or activated to enable function to continue
3) Structural changes then occur
4) Regeneration and Axonal Sprouting - growth of new nerve endings that connect to other undamaged nerve cells to form new pathways
5) Reformation of blood vessels
6) Recruitment of homologous (similar) areas on the opposite side of the brain
After a period of time, the function may switch back to the original side
7) Denervation supersensitivity to reduce the severity/extent of impairment and axons that do a similar job become arous to compensate for the last ones

Question 7

Evaluation (STRENGTH) - Practical Application

Answer 7

Plasticity research has helped in the area of neurorehabilitation

Following illness or injury to the brain spontaneous recovery slows down and after a while so physical therapy may be necessary to continue improvements in functioning

Movement therapy and electrical stimulation can be used to counter deficits in motor and cognitive functioning that may be experienced after a stroke

This shows that although the brain can fix itself further intervention is required to ensure complete recovery.

Question 8

Evaluation (STRENGTH) - Age and Plasticity

Answer 8

Functional plasticity tends to reduce with age
In childhood, the brain is used to adapting due to new experiences, as we get older this happens less

Ladina Bezzola et al (2012) -
Using fMRI researchers observed reduced motor activity in the novice golfers compared to a control group, suggesting more efficient neural representations after training
This shows that neuroplasticity does continue throughout the lifespan

Question 9

Evaluation (STRENGTH) - Support from Animal Studies

Answer 9

Early evidence of neuroplasticity and functional recovery was derived from animal studies

Hubel and Wiesel et al (1963) -
Involved sewing one eye of a kitten shut and analysing the brains cortical responses
Found the area of the visual cortex associated with the shut eye was not idle, but continued to process information from the open eye

Question 10

Evaluation (WEAKNESS) - Negative Plasticity

Answer 10

The brains ability to rewire itself can have maladaptive behavioural consequences

Medina et al (2007)
Prolonged drug use has been shown to result in poor cognitive functioning as well as an increased risk of dementia later in life

Ramachandran and Hirstein (1998) -
60-80% of amputees have been known to develop phantom limb syndrome
This is a continued experience of sensations in the missing limb as if it was still there
The sensations are usually unpleasant, painful and are thought to be due to cortical reorganisation in the somatosensory cortex as a result of limb loss

Question 11

Evaluation (WEAKNESS) - Cognitive Reserve

Answer 11

Schneider et al (2014) -
Evidence suggests that a persons, educational or attainment may influence how well the brain functionally adapt after injury
Discovered that the more time brain injury patients had spent in education, the greater their chance of a disability free recovery
2/5 of patience studied who had achieved disability free recovery had more than 16 years education, compared to about 10% of patients who had less than 12 years education