Biopsychology 4- plasticity, functional recovery, split-brain research and hemispheric lateralisation

Brain plasticity

The brain’s ability to change and adapt as a result of experience or learning.

Synaptic pruning

Weak or unused synaptic connections are removed and stronger ones strengthened.

Functional recovery

The brain’s ability to compensate for damaged areas after trauma by reorganising or forming new connections.

Axonal sprouting

Growth of new nerve endings that connect with undamaged neurons to reform networks.

Recruitment of homologous areas

When similar areas on the opposite hemisphere take over tasks of damaged regions.

Split-brain research

Research studying individuals who have had their corpus callosum severed to reduce epilepsy.

Corpus callosum

The bundle of fibres connecting the two hemispheres, allowing communication between them.

Left hemisphere functions

Language processing, analytic and logical tasks.

Right hemisphere functions

Spatial awareness, creativity, facial recognition.

Sperry’s findings

Each hemisphere can operate independently; left handles language, right handles visuospatial tasks.

What are the strengths of the plasticity and functional recovery theory?

+ Supporting evidence

• Maguire → high ecological validity, scientific.
  + Practical applications

• Contributed to neurorehabilitation → real-world value.

What are the limitations of the plasticity and functional recovery theory?

     – Negative plasticity

• Drug use/phantom limb pain illustrate maladaptive plasticity.
  – Individual differences

• Younger brains recover better (Elbert study showing higher plasticity in children).
  – Animal studies issues

• Much research based on rats → problems generalising to humans.

What are the strengths of the split-brain and hemispheric lateralisation theory?

+ Strength: groundbreaking research

• Sperry used highly controlled methods → reliable.
  + Demonstrates hemispheric specialisation

• Clear differences found → supports lateralisation.

What are the limitations of the split-brain and hemispheric lateralisation theory?

– Small, unusual sample

• Severe epilepsy patients → cannot generalise.
  – Some argue findings overstated

• Normal brains communicate, so real-life lateralisation is less clear-cut.
  – Conflicting evidence

• Functional plasticity suggests hemispheres compensate for each other.