Recent explorations in the neurosciences have been progressing towards an understanding of the relationship between brain structure and brain function. Having passed through an era which may be described as one of a localisationist philosophy, in which discrete brain areas were seen to subserve only discrete functions, the perspective of brain-behaviour relationships has advanced in recent years to an appreciation that a more holistic approach is not only heuristically valid, but is also most likely to lead to future advances. The close relationship between the mind and the brain has been appreciated since the time of Hippocrates when he opined 'men ought to know that from nothing else but thence [from the brain] comes joys, delights, laughter and sports, and sorrows, griefs, despondency and lamentations ... and by this same organ we become mad and delirious and fears and terrors assail us'. In the nineteenth century, particularly in France and Germany, descrip­ tions of what are now recognised to be independent neurological diseases emerged following empirical clinical observations. Investi­ gation led to the identification in many cases of underlying structural abnormalities which could be linked to pathological changes.