Plasticity and functional recovery of the brain after trauma Flashcards
What is plasticity?
The brains tendency to change and adapt as a result of experience and new learning.
How does a human brain develop throughout their life?
During infancy, the brain experiences a rapid growth in the number of synaptic connections it has, peaking at about 15,000 per neurone at 2-3 years. This is is about twice as many as there are in an adult brain.
As we age, rarely used connections are deleted and frequently-used connections are strengthened. This is known as synaptic pruning.
Maguire’s research into brain plasticity
She studied the brains of London taxi drivers and found significantly larger hippocampus than a control group.
The hippocampus is involved in the development of spatial and navigational skills.
As part of their training the cab drivers must take a complex test to test their recall of the city streets.
Strengths of plasticity.
Research suggests that there may be seasonal plasticity in the brain in response to environmental changes.
For example the suprachiasmatic nucleus shrinks in spring and expands in autumn.
However most of this research has been done on animals and may not generalise to humans.
Limitations of plasticity
It may have negative behavioural consequences.
Prolonged drug use leads to poorer cognitive functioning in later life, as well as increased risk of dementia.
60-80% of amputees have been known to develop phantom limb syndrome. Theses are usually to due with the somatosensory cortex.
This suggests that the brains ability to adapt to damage is not always beneficial
What is functional recovery?
A form of plasticity following damage through trauma, the brains ability to transfer or redistribute functions usually performed by a damaged area.
what are the three types of functional recovery?
axon sprouting
Denervation supersensitivity
Recruitment of homologous areas on opposite sides of the brain
What is axon sprouting?
The growth of new nerve endings which connect with other undamaged nerve cells to form new nervous pathways.
What is denervation supersensitivity?
Axons that do a similar job become aroused to a higher level to compensate for the ones that are lost.
This can have negative impacts such as pain receptors.
What is recruitment of homologous chromosomes on the opposite sides of the brain?
This means that specific tasks can still be performed.
For example, if Broca’s area was damaged on the left side of the brain, the right-sided equivalent would carry out its functions.
Strength of functional recovery.
Real-world application.
Understanding the processes involved in plasticity had led to neurorehabilitation. It has allowed for new therapies to be tried.
It has been helpful in medical processes.
Limitation of functional recovery.
The level of education may influence recovery rates.
Schneider revealed that the more time people with a brain injury had spent in education, the greater their chances of disability free recovery.
40% of those who achieved DFR had more than 16 years in education compared to about 10% of those who had less than 12 years in education.
This would imply that people with brain damage who have insufficient DFR are less likely to achieve full recovery.
