6.5 plasticity and functional recovery
Key Terms
| Term | Definition |
| ------------------- | ---------------------------------------------- |
| Plasticity | Brain’s ability to adapt/change |
| Functional recovery | Brain reorganising after injury |
| Synaptic pruning | Removing unused neural connections |
| Axonal sprouting | Growth of new nerve endings |
| Cognitive reserve | Brain resilience linked to education/intellect |
| Homologous areas | Corresponding regions in opposite hemisphere |
Specification Focus
Plasticity and functional recovery after trauma.
Neural plasticity = the brain’s ability to change/adapt due to experience.
Functional recovery = transfer/reorganisation of functions after damage.
1. Brain Plasticity
Definition
Brain plasticity refers to the brain’s ability to:
* change structure and function
* form new neural connections
* reorganise itself after learning or damage
Synaptic Pruning
* Frequently used connections strengthen.
* Rarely used connections are deleted.
* This helps the brain adapt efficiently.
Research Into Plasticity
Maguire et al. (2000) – London Taxi Drivers
Aim
Investigate whether learning/navigation changes brain structure.
Method
* Compared London taxi drivers with non-taxi-driver controls.
* MRI scans used.
Findings
* Taxi drivers had larger posterior hippocampi.
* Longer time spent taxi driving → larger hippocampus.
* Positive correlation found.
Conclusion
Learning experiences can physically alter the brain.
Draganski et al. (2006)
* Medical students scanned before and after exams.
* Increased grey matter observed after learning.
* Changes found in:
* posterior hippocampus
* parietal cortex
Conclusion
Learning can produce structural brain changes.
2. Functional Recovery After Trauma
Definition
Following injury, undamaged brain areas can:
* reorganise
* compensate
* take over lost functions
This is a form of neural plasticity.
Spontaneous Recovery
* Happens soon after trauma.
* Brain naturally repairs/reorganises itself.
* Recovery slows after weeks/months.
* Rehabilitation may then be needed.
3. Mechanisms of Functional Recovery
Axonal Sprouting
* New nerve endings grow.
* Connect with undamaged neurons.
* Creates new pathways.
Denervation Supersensitivity
* Neurons become more sensitive after losing input.
* Helps compensate for lost functioning.
Recruitment of Homologous Areas
* Opposite hemisphere takes over functions.
* Example:
* right hemisphere may take over speech after left hemisphere damage.
4. Evaluation of Plasticity
Strengths
Real-World Application
* Research helps rehabilitation techniques.
* Example:
* constraint-induced movement therapy for stroke patients.
Cognitive Reserve
* Higher education/cognitive ability linked to better recovery.
* Schneider et al. (2014):
* more educated patients recovered better from brain injury.
Lifelong Plasticity
* Bezzola et al. (2012):
* older adults showed brain changes after golf training.
* Suggests plasticity continues throughout life.
Limitations
Negative Plasticity
Plasticity can have harmful effects:
* drug abuse linked to cognitive decline
* phantom limb syndrome may occur due to cortical reorganisation
Small Sample Sizes
Some recovery studies use:
* very small samples
* no control groups
→ lowers reliability/generalisability.
Animal Research Issues
* Much seasonal plasticity research done on animals.
* Humans may differ significantly.
5. Functional Recovery Case Study – Gabby Giffords
Background
* US politician shot in the head (2011).
* Severe brain injury.
Recovery
With rehabilitation she regained:
* walking
* speech
* reading/writing
Importance
Demonstrates remarkable brain plasticity and recovery potential.
6. Meditation and Mindfulness
Research suggests meditation can alter brain structure/function.
Findings
Experienced meditators showed:
* thicker cortex
* increased grey matter
* changes in:
* hippocampus
* anterior cingulate cortex
Implication
Everyday experiences can physically reshape the brain.