of the SST is triggered by saliency processing of the stop signal (Cai et al., 2014; Cai et al., 2015; Hampshire and Sharp, 2015) and a proper contrast would have to index this saliency response. Thus, a contrast of SS>GS reflects how cerebral responses to the infrequent, stop signal “kick-start” the inhibitory process and those regional activations in correlation with SSRT mediate this linked neural activity for successful inhibition. Conversely, a contrast of SS>SE would identify regional activities that are suppressed by saliency and undermine the link of saliency response to motor inhibition. With these considerations, it is likely that what we have seen earlier with the latter contrast primarily reflected a diminished preparatory motor activity (in the pre-SMA) during SE, as compared to SS; that is, less motor preparation is conducive to more efficient inhibitory control. Both saliency response (to the stop signal) and diminished motor preparation (as a result of response caution or top-down influence of cognitive control) are critical to successful inhibition. Both of these processes can be captured by a contrast of SS>GS, but not SS>SE. Therefore, in the current study, we have opted to employ the contrast of SS>GS in data analyses. We would also
