A supramodal limbic-paralimbic-neocortical network supports goal-directed stimulus processing

Limited processing resources are allocated preferentially to events that are relevant for behavior. Research using the novelty "oddball" paradigm suggests that a widespread network of limbic, paralimbic, and association areas supports the goal-directed processing of task-relevant target events. In that paradigm, greater activity in diverse brain areas is elicited by rare task-relevant events that require a subsequent motor response than by rare task-irrelevant novel events that require no response. Both stimulus infrequency (unexpectedness) and novelty, however, may contribute to the pattern of activity observed using that paradigm. The goal of the present study was to examine the supramodal neural activity elicited by regularly occurring, equiprobable, and non-novel stimuli that differed in the subsequent behavior they prescribed. We employed event-related functional magnetic resonance imaging (fMRI) during auditory and visual versions of a Go/NoGo task. Participants made a motor response to the designated "Go" (target) stimulus, and no motor response to the equiprobable "NoGo" (nontarget) stimulus. We hypothesized that task-relevant Go events would elicit relatively greater hemodynamic activity than would NoGo events throughout a network of limbic, paralimbic, and association areas. Indeed, Go events elicited greater activity than did NoGo events in the amygdalahippocampus, paralimbic cortex at the anterior superior temporal sulcus, insula, posterior orbitofrontal cortex, and anterior and posterior cingulate cortex, as well as in heteromodal association areas located at the temporoparietal junction, anterior intraparietal sulcus and precuneus, and premotor cortex. Paralimbic cortex offers an important site for the convergence of motivational/goal-directed influences from limbic cortex with stimulus processing and response selection mediated within the frontoparietal areas. (C) 2004 Wiley-Liss, Inc.