Although we saw general deficits on STOP-change trials, we did not observe disruption in behavioral measures related to conflict adaptation. Interestingly, however, at the neural level, firing to the first cue took longer to emerge and was attenuated on sS trials in control rats but not in rats with ACC lesions. Thus, it appears that ACC contributes to the modulation of downstream neural signals after having experienced a trial that required adjustment, either directly, through an intermediate, or in parallel with other structures [e.g., medial prefrontal cortex, orbitofrontal cortex (24, 25)]. Consistent with this observation, when ACC was lesioned, firing in DMS during error trials for responses made into the response field was not dampened prior to illumination of the second cue. Overall, these results suggest that, in addition to ACC modulating DMS to reactively adjust directional signals after presentation of STOP cues, ACC also acts by putting a brake on downstream targets to attenuate responding to the first cue light.
