Salience and attentional modulation of response control

Inhibitory control relies on multiple interacting processes and is influenced by salience and attentional modulation, both of which affect the efficiency of detecting a signal that instructs inhibition. This, in turn, can influence the ability to suppress an ongoing action. Therefore, failure to inhibit a response may result either from a failure to detect the stop signal or from an inhibitory implementation deficit. To dissociate these processes, a Bayesian behavioral model known as the BEESTS model was applied to two human studies conducted by using modified versions of the Stop Signal Task, in which attentional cues toward the stop signal or the visual salience of the stop signal were manipulated. In the attentional cueing experiment, on stop trials, a cue indicating the spatial location of the upcoming stop signal was presented. Specifically, in valid stop trials, the stop signal appeared in the same direction indicated by the cue; in invalid stop trials, the stop signal appeared in the direction opposite to that indicated by the cue. We observed that in valid trials, the inhibitory process was triggered more easily than in invalid trials. In the salience experiment, we observed that more salient stop signals facilitated the triggering of the inhibitory process and its speed, making inhibition faster compared with conditions in which the signal is less salient. Similar effects were also observed in macaque monkeys. Building on this cross-species similarity, we analyzed neuronal dynamics in the premotor cortex of macaque monkeys during the salience experiment. The data suggest a possible neural signature associated with failures in triggering the stop process.