A thesis submitted in partial fulfilment of - Queen Margaret University

eorganisation in hemiplegic stroke patients. Preliminary results are reported to
be promising. Interestingly, significant subcortical changes have also been
demonstrated in patients who present with hysterical conversion i.e. they
experience a loss or impairment of function that cannot be explained by any
known organic neurological disease, indicating plasticity of brain regions
(Vuilleumier, Chicherio, Assal, Schwartz, Slosman and Landis, 2001; Marshall,
Halligan, Fink, Wade and Frackowiak, 1997) which then resolved after the
conversion symptoms had diminished (Vuilleumier et al., 2001).
Cortical plasticity has also been demonstrated with adults who are born with
physical difficulties such as syndactyly (webbed-finger syndrome), where the
fingers of individuals are webbed together from birth with the fingers being
unable to move independently from each other (Robertson, 1999). The sensory
map on their brains reflected this physical anomaly where clusters of neurones
for each individual finger were merged into just one area and the brain
considered the fingers as one entity. Brain-imaging techniques demonstrated
cortical reorganisation following surgery which separated the fingers allowing
them to move independently from each other and it was observed that each
finger developed its own separate neurone base. Robertson (1999) advises that
this is a result of Hebbian learning where neurones, which begin to fire
simultaneously, consequently wire together as the individual fingers begin to
move independently from each other and neurones for each individual finger
became connected to its own neuronal base. This process and its reverse have
also been observed in animal studies.
The evidence presented above demonstrates that physical and motor learning
occurs in the adult brain demonstrated by increased and complex neuronal
connections (Robertson, 1999). Abundant evidence therefore demonstrates that
the intact healthy adult brain is amenable to physical change (plasticity) despite
earlier assertions that this is only possible in the developing brain. In the next
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