Executive control, willed actions, and nonconscious processing

Neuroimaging studies have identified a number of cortical areas involved in the executive control of conscious actions. The areas most frequently impl icated are prefrontal and cingulate cortices. Evidence suggests that both o f these areas may be essential for executive control of willed action. Pref rontal cortex, however may be responsible for the initial processing. Execu tive control is usually discussed with reference to willed actions and is a ssumed to regulate complex cognitive responses. Although many implicit proc esses involve complex responses, it is not known whether these actions are also controlled by executive processes. Significantly some implicit tasks l ike those involving motor sequence learning and cross-modality priming acti vate the same areas of prefrontal cortex that are implicated in the executi ve control of willed actions. It is, however, not clear whether a single ex ecutive process controls both implicit and explicit processes, or the impli cit processes are regulated by a separate set of executive control having d istinct neuroanatomical location and processing properties. (C) 2000 Wiley- Liss, Inc.