Plasticity and functional recovery of the brain after trauma BP Flashcards
(19 cards)
plasticity
this describes the brain’s tendency to change and adapt as a result of experience and new learning
functional recovery
a form of plasticity, the brain’s ability to redistribute or transfer functions usually performed by a damaged area to an undamaged area
Gopnik et al
found that the rapid growth of synaptic connections peaks at 15,000 per neuron at 2-3 years old
Brain plasticity
Can change throughout life
synaptic pruning definition
synaptic connections reduced in adult brains as rarely used connections are forgotten and regularly used ones are strengthened
synaptic pruning
enables lifelong plasticity where neural connections are formed in response to new demands in the brain
Maguire et al studied brains of london taxi drivers
- Higher volume of grey matter in posterior hippocampus than in a matched control group
- Associated with the development of spatial and navigational skills
- Cabbies take ‘the knowledge test’ for London
- Assesses their recall of streets etc
- This alters the structure if the cabbies brains
- Positive correlation between length in the job and structural difference in brain
Draganski et al supporting cabbie study
- imaged brains of medical students 3 months before and after final exams
- Learning-induced changes occurred in the posterior hippocampus and the parietal cortex
after brain trauma
Healthy brain areas take over damaged, destroyed or missing areas.
Neuroscientists found that this can occur spontaneously or after several weeks/months (rehabilitative therapy may be required).
What happens in the brain during recovery?
Rewires and reorganises itself by forming new synaptic connections. Secondary neural pathways are activated to allow functioning to continue (Doidge)
Secondary neural pathways supported by numerous structural changes like …
- Axonal sprouting
- Denervation supersensitivity
- Recruitment of homologous areas (opposite side of the brain)
Axonal sprouting
growth of new nerve endings which connect with other undamaged nerve cells to form new neural pathways
Denervation supersensitivity
this occurs when axons that so a similar job become aroused to a higher level to compensate for the ones that are lost (can have negative consequences like pain)
Recruitment of homologous areas (opposite side of the brain)
specific tasks can still be performed
Seasonal brain changes
- In response to environmental changes
- The nucleus involved with sleep shrinks in spring and expands in autumn in animals (Tramontinand Brenowitz)
- Can’t be generalised to humans
cognitive reserve
Level of education may influence recovery rates
* Schneider et al said that the more education the higher chances of having a disability-free recovery
* 40% of those with DFR had 16 years of education
rwa
Contributed to neurohabilitation
* Understanding how axonal growth is possible encourages new therapies to be tried
* Constraint-induced movement therapy
The research is useful and helps medical professionals with any needed interventions
negative plasticity
May have negative behavioural consequences
* Brains adaptation to prolonged drug use leads to poorer cognitive functioning in later life and an increased risk of dementia (Medina et al)
* 60-80% of amputees develop phantom limb syndrome, which is unpleasant and painful and due to cortical reorganisation in the somatosensory cortex (Ramachandran)
The brain’s ability to adapt to change is not always beneficial
age and plasticity
Brain plasticity may be a life-long ability
* In general it reduces with age
* Bezzola et alfound that 40 hours of golf training makes changes in neural representations of movement in people aged 40-60
* Observations of increased motor cortex were made using fMRIs in novice golfers compared to a control group
* More efficient neural representations after training
Neural plasticity can continue throughout life.
