AROUSAL SYSTEMS AND ATTENTIONAL PROCESSES

Unitary concepts of arousal have outlived their usefulness and their p sychological fractionation corresponds to a similar chemical different iation of the reticular formation of the brain. Neurobiological charac teristics of the monoaminergic and cholinergic systems can be describe d in terms of their anatomical, electrophysiological and neurochemical properties. Functional studies suggest that the coeruleo-cortical nor adrenergic system, under certain circumstances, is implicated in proce sses of selective attention, that the mesolimbic and mesostriatal dopa minergic systems contribute to different forms of behavioural activati on, and that the cortical cholinergic projections have fundamental rol es in the cortical processing of signals, affecting attentional and mn emonic processes. The ascending serotoninergic systems contribute to b ehavioural inhibition and appear to oppose the functions of the other systems in several ways. (C) 1997 Elsevier Science B.V.