Plasticity And Functional Recovery Of The Brain After Trauma Flashcards
What is brain plasticity?
The brain’s ability to change throughout life.
What happens to synaptic connections during infancy?
The brain experiences rapid growth in the number of synaptic connections.
How many synaptic connections does a neuron have at 2-3 years old?
About 15,000 per neuron.
What is synaptic pruning?
The process where rarely used connections are removed and frequently used connections are strengthened.
Occurs as we age and enables lifelong plasticity
What is the significance of new neural connections?
They are made in response to new demands on the brain.
What did Maguire et al study in their research?
The brains of London taxi drivers.
What was found in the brains of London taxi drivers compared to a control group?
More grey matter in the posterior hippocampus.
What is the function of the posterior hippocampus?
It is linked to spatial and navigational skills.
What is ‘The Knowledge’ test?
A test that assesses taxi drivers’ recall of street names and possible routes.
Argued learning experiences alters structure of brain
- longer taxi drivers been working, more obvious structural difference
What did Draganski et al find in their study of medical students?
Learning-induced changes occurred in the posterior hippocampus and parietal cortex.
What is functional recovery?
The ability of unaffected areas of the brain to adapt and compensate for damaged areas after an injury or stroke.
Example of neural plasticity
Can occur quickly then slow down after weeks or months
- individual may require rehabilitative therapy at this point
What occurs during recovery within the brain?
Rewires and reorganises itself through forming new synaptic connections near the area of damage
Secondary neural pathways that wouldnt typically be used are activated
- enables functioning to continue often in the same way as before
What structural changes occur during recovery after brain trauma?
- Axonal sprouting
- Denervation super sensitivity
What is axonal sprouting?
The growth of new nerve endings that connect with undamaged nerve cells to form new neuronal pathways.
What is denervation super sensitivity?
When axons that perform similar jobs become more aroused to compensate for lost axons.
What happens when specific areas of the brain are damaged?
Similar areas on the opposite side of the brain may take over the function.
What’s a strength of plasticity related to lifespan?
It may be a lifelong ability despite it reducing with age
Bezzola found 40 hours of golf training changed the neural activity in 40-60 yr olds
- used fMRI scans and observed increased motor cortex activity in beginner golfers
What’s another strength of plasticity relating to seasons?
May be seasonal plasticity in response to environment changes
Suprachiamatic nucleus regulates sleep/wake cycle
- evidence shows that this shrinks during the spring and expands during autumn
What’s a strength of functional recovery?
Real world application through contributing to the world of neurorehabilitation
Understanding axonal growth is possible = new therapies
Constraint-induced movement therapy used in stroke patients
- patient practices using affected part of the body while unaffeced arm is restrained
What’s important to note about seasonal plasticity as a strength?
Most research done on birds
Hard to apply and generalise to humans
- human brains more complex
- limits validity
What’s a limitation of plasticity?
May have negative behaviour consequences as brains adaptation to prolonged drug use = poorer cognitive functions in future and increased risk of dementia
As well as:
60-80% of amputees develop phantom limb syndrome (feeling like missing limb still there)
- due to cortical reorganisation in somatosensory cortex as a result of limb loss
What limitations exist in research on functional recovery?
Level of education may influence recovery rates as Schneider et al found brain injury patients have greater chance of full recovery if they had spent more time in education
Implies lesser educated people may not fully recover
- research typically includes small samples and no control groups (hard to generalise)
