Plasticity & functional recovery of the brain after trauma Flashcards
What is brain plasticity?
The idea that the brain is like plastic how it changes & adapts as a result of experience and new learning
When does the brain experience a rapid growth in synaptic connections?
During infancy it peaks at around 15000 synapses per neuron at the ages 2-3
What happens to these synaptic connections as we age?
The rarely used connections are deleted whilst the frequently used ones are strengthened
What were the original thoughts on brain plasticity & how has it changed after more recent research?
- Changes to the brain were restricted to the developing brain and an adult brain has a fixed structure & function
- More research suggests that neural connections can change at any time in life & new connections can form as a result of learning and experience
What research did Mechelli et al do into plasticity?
He found a larger parietal cortex in bilingual people’s brain compared to monolingual person’s brain
What happens to unaffected areas of the brain after a physical injury or other forms of trauma?
It is able to adapt and compensate for the damaged areas
What is functional recovery?
A form of plasticity where the brain is able to redistribute or transfer functions usually performed by the damaged areas after damage through trauma
What do neuroscientists suggest about the process of functional recovery?
It can happen quickly after trauma (spontaneous recovery) and then slow down after several weeks or months
What happens in the brain after recovery?
- The brain is able to reorganise itself & form new synaptic connections close to the damaged area
- Secondary neural pathways that wouldn’t typically be used to carry out certain functions are activated to enable functioning to continue
What are the 3 structural changes that happen in the brain during recovery?
Axon sprouting, reformation of blood vessels & recruitment of homologous areas on the opposite side of the brain to perform specific functions
What is axon sprouting?
The growth of new nerve endings which connect with other undamaged nerve cells to form new pathways
What is reformation of blood vessels?
Damaged blood vessels are reformed to ensure the brain functions in affected areas
Evaluation: Practical application
- Understanding processes in plasticity has contributed to neurorehabilitation
- Since spontaneous recovery slows down after several weeks/months a form of physical therapy may be required to maintain improvements in functioning
- Techniques may include movement therapy & electric stimulation of the brain to counter deficits in motor/cognitive functioning from a stroke for e.g.
- shows that the brain may be capable to ‘fix itself’ to an extent and further intervention needed for success
Evaluation: Negative plasticity
- The brain’s ability to rewire itself may have negative behavioural consequences
- Prolonged drug use shown to result in poorer cognitive functioning & increased risk of dementia
- 60-80% of amputees have been known to develop phantom limb syndrome where they experience painful sensations in the missing limb area which are thought to occur due to reorganisation of somatosensory cortex
Evaluation: Age and plasticity
- functional plasticity tends to reduce with age
- the brain is more likely to reorganise in children as the brain is still changing based on new learning & experiences
- Ladina Bezzola et al demonstrated how 40 hours of golf training produces reduced movement in pps aged 40-60
- reduced motor cortex activity observed by fMRI scans compared to control group
- shows that neural plasticity does continue with age
Evaluation: Support from animal studies
- early evidence of neuroplasticity & functional recovery came from animal studies
- Hubel & Wiesel’s study involved sewing one eye of a kitten shut & analysing the brain’s cortical responses
- it was found that the area of the visual cortex associated with the shut eye wasn’t idle but continued to process information from the open eye
