The prominent role of stimulus processing: cholinergic function and dysfunction in cognition.

PURPOSE OF REVIEW The present review develops a framework from which to understand the role of the cholinergic system in healthy cognition and in cognitive dysfunction. Traditionally, the cholinergic system has been thought to have direct influence on cognitive processes such as working memory and attention. Although the influence of cholinergic function on stimulus processing has been long appreciated, the notion that cholinergic effects on stimulus processing is the mechanism by which acetylcholine influences cognitive processes has only more recently been considered. RECENT FINDINGS Literature supporting the hypothesis that cholinergic modulation influences cognitive functions through stimulus processing mechanisms has been growing for over a decade. Recent conceptualizations of the developing literature have argued for a new interpretation to an old and developing literature. SUMMARY The argument that cholinergic function modulates cognitive processes by direct effects on basic stimulus processing extends to cognitive dysfunction in neuropathological conditions including dementia and mood disorders. Memory and attention deficits observed in these and other conditions can be understood by evaluating the impact of cholinergic dysfunction on stimulus processing, rather than on the cognitive function in general.