Varieties of inhibition: manifestations in cognition, event-related potentials and aging

Inhibition and facilitation are the driving forces of selective attention. Some important and still unresolved conceptual issues with respect to facil itation and inhibition are: (a) are they separate processes with different neural substrates (b) what is their time course and (c) what is their tempo ral locus: do they operate at the level of early sensory, central or respon se-related selection processes? In this introductory article we present a o verview of relevant experimental paradigms that are also (in part) reflecte d in the contributions of this special volume, and discuss the major behavi oral and psychophysiological findings from which inhibitory processes have been inferred. The global pattern of the results indicates that there are m ultiple inhibitory systems and processes in the central nervous system that may be expressed in many different ways. Our overview of paradigms togethe r with the aging-related literature leads us to propose a framework for con ceptualizing inhibitory processes in terms of three distinct but interactin g neural systems at the level of anterior and posterior cortices and the br ain stem. (C) 1999 Elsevier Science B.V. All rights reserved. PsycINFO. cla ssifications: 2346; 2530; 2860; 3297.