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Abstract:
Abstract: We have argued previously that the anterior
cingulate cortex (ACC) contributes to executive control by
detecting processing conflicts signaling the need to engage
attention. Previous studies show ACC activation with response
conflict, however it is unresolved whether other kinds of conflict,
such as those arising at the stimulus level, also activate ACC.
This has implications for the mechanisms by which conflict leads to
increased ACC activation. In order to clarify this issue we used
functional magnetic resonance imaging to investigate ACC activity
in subjects performing a modified Eriksen flanker task. This task
involved targets flanked by either congruent stimuli (C);
stimulus-incongruent stimuli that mapped onto the same response,
eliciting conflict at the level of target detection (SI); or
response-incongruent stimuli that mapped onto incompatible
responses, eliciting both target detection conflict and response
conflict (RI). In a preliminary analysis of 6 subjects' dat! ! a,
reaction times increased with the level of conflict
(C<SI<RI), but ACC activity showed a transient increase
only in RI trials, not in SI trials. Further analyses of a larger
group of subjects will be presented. If these results prove
reliable they suggest that the conflict monitoring function of the
ACC may be limited to detecting conflict between multiple
incompatible response tendencies.
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