Plasticity and functional recovery of the brain Flashcards
What is plasticity?
The brain’s tendency to change and adapt as a result of experience and new learning. This generally involves the growth of new connections
What did Gopnick et al claim?
During infancy the number of synaptic connections peak at 15,000 at the age of 2-3 years.
What is synaptic pruning?
As we age, rarely used connections are deleted and frequently used connections are strengthened - synaptic pruning
Recent research suggests neural connections can change or be formed any time, due to learning and experience
What evidence is there to show continual brain alteration (most famous)
- explain
Magurie - found that taxi drivers brains change shape to deal the the complications of the job
The posterior hippocampus was much larger than control groups. It is the bit that is associated with spatial skills and navigation
The effect had gone after they had retired
Our brains can change shape ‘real time’ to deal with new skills, situations and damage
What other research is there for continual brain alteration? (2)
- explain
Draganski - imaged the brains of medical students three months before and after final exams. Learning induced changes were seen in the posterior hippocampus and the parietal cortex, presumably as a result of learning for the exam
Mechelli - found a larger parietal cortex in the brains of people who were bilingual compared to matched monolingual controls
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 to other, undamaged area
Neuroscientists - process occurs quickly after trauma (spontaneous recovery) and then slows down - at which point the person may require rehabilitative therapy
How is the brain able to rewire itself?
The brain is able to rewire and reorganise itself by forming new synaptic connections close to the area of damage
Secondary neural pathways that would not typically be used to carry out certain functions are activated to enable functioning to continue
State 3 structural changes in the brain
Axonal sprouting
Denervation supersensitivity
Recruitment of homologous (similar) areas
Describe axonal sprouting
Growth of new nerve endings which connect with other undamaged cells to form new neuronal pathways
Describe denervation supersensitivity
Axons that do a similar job become aroused to a higher level compensate for the ones that are lost
Describe recruitment of homologus (similar) areas
The opposite side of the brain takes over specific tasks e.g language production
EVALUATION: Practical application
Understanding of the mechanisms underlying plasticity has improved the area of neurorehabilitation.
Physical therapy may be necessary for maintaining improvements in functioning after a brain injury or illness because spontaneous recovery tends to slowdownafter a few weeks. Strategies to counteract the deficiencies in motor and/or cognitive performance that may be seen after a stroke, for example, include movement therapy and electrical stimulation of the brain.
This indicates that while the brain may heal itself to some extent, further help is needed for the healing process to be fully effective.
EVALUATION: Research support
Research supports up the concept of brain plasticity. ResearcherKuhn et al. discovered that after participants played video games for 30 minutes over the course of two months, there was a significant increase in grey matter in multiple brain regions.
This is significant because Kuhn provides strong evidence based on brain plasticity, demonstrating how experience—such as playing video games—can alter the fundamental structure of the brain.
EVALUATION: Age and plasticity
As we age, functional plasticity tends to decrease. Because the brain is constantly changing due to learning and experience, it is more likely to undergo reorganisation during childhood.
Having said that, Ladina Bezzola et al. (2012) showed how participants aged 40 to 60 saw alterations in their brain representation of movement after 40 hours of golf training. The researchers found that the inexperienced golfers had lower motor cortex activity using fmRI when compared to a control group, which may indicate more effective neural representations following instruction.
This demonstrates that brain plasticity does not stop during a person’s lifetime.
EVALUATION: Neural plasticity may be related to cognitive reserve
Evidence suggests a person’s educational attainment may influence how well the brain functionally adapts after injury
Schneider - found the more time brain injury patients had spent in education ( indicated their cognitive reserve) and their chances of a disability free recovery (DFR)
40% of patients who achieved DFR had more than 16 years education compared to about 10% of patients who had less than 12 years of education
This suggests that cognitive reserve is a crucial factor in determining how well the brain adapts after trauma
