Plasticity and functional recovery of the brain after trauma Flashcards
What is plasticity?
this describes the brain’s tendency to change and adapt (functionally and physically) as a result of experience and new learning
When does the brain experience rapid growth in the number of synaptic connections? What does this peak at and at what age?
during infancy
this peaks at approx 15,000 at 2-3 years
How many more synaptic connections are there in an infant brain compared to an adult brain?
twice as many
What happens to rarely used connections as we age?
they are deleted
What happens to frequently used connections as we age?
they are strengthened
What is the process of synaptic connections being deleted and strengthened called?
synaptic pruning
What did people originally think about brain plasticity (or the lack of it)?
changes were restricted to the developing brain in childhood
adult brain, having moved beyond the critical period, would remain fixed and static in terms of structure and function.
What has recent research suggested about neural connections?
at any time in life they can change or form as a result of learning and experience
What did Maguire et al (2000) do?
studied the brains of London taxi drivers and found that there was significantly more volume of grey matter in the posterior hippocampus than in a matched control group.
This part of the brain is associated with the development of spatial and navigational skills.
What do Maguire’s results suggest?
the results suggest that ‘the knowledge’ test altered the structure of their brains. The longer they had been in their job, the more pronounced the structural differences.
What did Draganski et al (2006) do and find?
imaged brains of medical students three months before and after exams
found learning induced changes in the posterior hippocampus and parietal cortex
What did Mechilli et al (2004) find?
found a larger parietal cortex in the brains of people who were billingual compared to matched monolingual controls
What field has understanding the processes of plasticity contributed to?
neurorehabilitation
What may be required to maintain improvements in functioning following illness or injury to the brain?
physical therapy
What has prolonged drug use been shown to result in?
poorer cognitive functioning as well as an increased risk of dementia
What percentage of amputees have experienced phantom limb syndrome? What is this?
60-80%
the continued experience of sensations in the limb which has been amputated as if it was still there. thought to be due to cortical recognisation in the somatosensory cortex.
What is 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)
Following physical injury or other forms of trauma what can unaffected areas of the brain do?
adapt and compensate for the damaged or even destroyed areas
How is the brain able to rewire and reorganise itself?
by forming new synaptic connections. secondary neural pathways are activated or ‘unmasked’ to enable functioning to continue often in the same way as before
What is axonal sprouting?
the growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways
What structural changes occur in functional recovery?
axonal sprouting
recruitment of homologous areas on the opposite side of the brain
reformation of blood vessels
Describe recruitment of homologous areas in terms of Broca’s area
if Broca’s area was damaged on the left side of the brain, the right sided equivalent would carry out its functions
Does functional plasticity increase or reduce with age?
reduce - the brain has greater propensity for reorganisation in childhood as it is constantly adapting to new experiences and learning
Bezzola et al (2012)
demonstrated how 40 hours of golf training produced changes in neural representation of movement in participants aged 40-60.
Using fMRI, the researchers observed reduced motor cortex activity in the novice golfers compared to the control group, suggesting more efficient neural representation after training
this shows that neural plasticity does continue throughout the lifespan
Schneider et al (2014)
found that the more time a brain injury patient had spent in education (which was taken as an indicator of their cognitive reserve) the greater their chance of a disability free recovery. 2/5 of patients studied who achieved DFR had more than 16 years education compared to 10% of patients who had less than 12 years of education.
