ABSTRACT
The decade of the brain has coincided with a new rapprochement between neurology and psychiatry, and the emergence of neuropsychology as both a research and a clinical discipline. Neuroimaging, moreover, has provided a new window on the interface between brain and mind, whether in sickness or in healthÐand indeed the latter distinction, in the context of neuropsychiatry, should itself be seen as involving a continuum, rather than a dichotomy, a continuum that re¯ects fundamental dimensions of personality. Thus those cognitive and behavioural aspects of interest to the neuropsychiatrist necessarily involve circuitry, the frontostriatal system, which underlies our very personal identities, as frugal, exploratory, rash, paranoid, depressive, hyperactive, obsessive, profane, salacious, or restrained. Indeed our highly evolved frontal regions, as the seat of our personalities, may underlie the very essence of our humanity. The dorsolateral prefrontal cortex, with associated frontostriatal circuitry, may be concerned with the highest cognitive or executive functions, including the setting of global plans, strategies, and schemata, the capacity to operate via self-direction or without external guidance, the organisation of new behaviours, cognitive ¯exibility, the maintenance or shifting of set and attention, and general problem solving and judgement. The lateral orbitofrontal cortex and associated circuitry may be involved with self-monitoring and the inhibition of inappropriate behaviours. The anterior cingulate and associated circuitry may mediate intentionality, the initiation of action, and focused attention.
