Anticipatory activity in anterior cingulate cortex can be independent of conflict and error likelihood

Abstract

Previous studies have found no agreement on whether anticipatory activity in the anterior cingulate cortex (ACC) reflects upcoming conflict, error likelihood, or actual control adjustments. Using event-related functional magnetic resonance imaging, we investigated the nature of preparatory activity in the ACC. Informative cues told the participants whether an upcoming target would or would not involve conflict in a Stroop-like task. Uninformative cues provided no such information. Behavioral responses were faster after informative than after uninformative cues, indicating cue-based adjustments in control. ACC activity was larger after informative than uninformative cues, as would be expected if the ACC is involved in anticipatory control. Importantly, this activation in the ACC was observed for informative cues even when the information conveyed by the cue was that the upcoming target evokes no response conflict and has low error likelihood. This finding demonstrates that the ACC is involved in anticipatory control processes independent of upcoming response conflict or error likelihood. Moreover, the response of the ACC to the target stimuli was critically dependent on whether the cue was informative or not. ACC activity differed among target conditions after uninformative cues only, indicating ACC involvement in actual control adjustments. Together, these findings argue strongly for a role of the ACC in anticipatory control independent of anticipated conflict and error likelihood, and also show that such control can eliminate conflict-related ACC activity during target processing. Models of frontal cortex conflict-detection and conflict-resolution mechanisms require modification to include consideration of these anticipatory control properties of the ACC.

Figure 1.

Experimental paradigm. Depicted are the informative and uninformative cues and examples of congruent, incongruent, and neutral targets with the word “right.” Green cues were always followed by congruent targets, red cues were always followed by incongruent targets, and yellow cues were always followed by neutral targets. Gray cues could be followed by either one of the three target conditions and, hence, were uninformative. The task was to indicate the direction denoted by the word by pressing a left or right button.

Figure 2.

Behavioral results. Mean response times and error rates (E%) of congruent, neutral, and incongruent target conditions preceded by informative and uninformative cues. Error bars represent SEM.

Figure 3.

ACC activity. A, Group maps showing increased ACC activity (Talairach coordinates: x = −9, y = 14, z = 37) for informative cues compared with uninformative cues (thresholded at p < 0.001 and minimal cluster size of 50 mm³). B–D, Mean β weights for the cues (B), mean β weights for the informed Stroop targets (C), and mean β weights for the uninformed Stroop targets (D) in the ACC region, showing an effect of informative cues versus uninformative cues. Error bars represent SEM. L, Left; R, right.