Biopsych: Plasticity and functional recovery of the brain Flashcards
What’s brain plasticity?
Refers to the brain’s ability to modify its own structure and function as a result of experience.
What’s plasticity as a result of life experience
during infancy the brain experiences rapid growth in the number of synaptic connections it has peaking at approx 15,000 at age 2-3 years. This equates to about twice as many an adult brain. As we age, rarely used connections deteriorate and frequently used connections are strengthened, a process known as synaptic pruning. Recent research suggests that existing neural connections can change or formed at any time in life, as a result of learning and experience (plasticity).
What’s Maguire et al’s research (2000)
Conducted MRI scanning on London taxi drivers to investigate grey matter density in regions of the brain.
He found that their were significantly more grey matter in the posterior hippocampus than the matched control group. The hippocampus is associated with spatial and navigational functioning. Shows a positive correlation between the amount of time on the job and structural development. This suggests that as taxi drivers memories the streets fro ‘The Knowledge’ test, the structure of the brain changes, providing evidence for plasticity.
What’s functional recovery?
Refers to the recovery of abilities and mental processes that have been compromised as a result of a brain injury or disease.
How are the brain after trauma and functional recovery linked?
Following physical injury or other forms of trauma like a stroke, unaffected areas of the brain are often able to adapt and compensate for those areas that are damaged.
The functional recovery that may occur in the brain is an example of brain plasticity.
Healthy brains areas may may take over the functions of the damaged, destroyed or even missing areas.
Neuroscientists suggest that this process can occur quickly after trauma (spontaneous recovery) and then slow down after several weeks or months. At this point the individual may require rehabilitative therapy to further their recovery.
What are the 4 mechanisms for functional recovery?
1) Axonal sprouting – growth of new nerve endings which connect with other in damaged nerve cells (re)forming neural pathways.
2) Neuronal unmasking – dormant synapses (neural activity in these areas previously weren’t needed) become activated due to higher rate of neural input required by the rest of the undamaged brain. Spread of activation leads to new structure development.
3) Stem cells – implanted unspecialised cells that can become nerve cells. Scientists could directly replace dead cells, ‘rescue’ injured cells, or form links with healthy brain areas that now can carry out the lost function.
4) Using similar areas on the opposite side of the brain for compromised tasks
What are the 4 AO3 points for plasticity and functional recovery of the brain
+Research evidence of plasticity
+Research evidence for functional recovery and stem cells
-Unreliable (functional recovery)
-limitation of neural plasticity
(+AO3) What’s research evidence of plasticity
Potential maladaptive and negative behavioural consequences. Prolonged drug use causes poorer cognitive functioning and a higher risk of dementia due to neural changes. 60-80% of amputees experience phantom limb syndrome due to the re-writing of somatosensory cortex. This shows that brain plasticity doesn’t always account for damaged brain areas.
(+AO3) What’s the research evidence for functional recovery and stem cells
Researchers randomly assigned rats with brain trauma to two groups. One group with stem cell implants and the other group without. Stem cell rats showed clear development of neuron-like cells in the area of injury. ‘Solid streak cells to injured area.’ This wasn’t evident in control group, which shows evidence of functional recovery through stem cells.
(-AO3) How is functional recovery unreliable ?
Assumed all brains respond to trauma in the same way. Research suggests educational attainment determines whether the brain will work post-trauma. Positive correlation between time in education pre-injury and chance of disability-free recovery suggesting that functional recovery is an oversimplified theory.
(-AO3) What’s a limitation of neural plasticity?
Researcher’s sewed one eye shut and analysed the brain’s responses. The area of the visual cortex associated with the shut eye still worked to carry out processing info for the open eye. This shows that when losing function in an area is can change role thus, showing evidence of brain plasticity.
