Neural mechanisms underlying distractor suppression guided by spatial cues

A growing body of research demonstrates that distracting inputs can be proactively suppressed via spatial cues, nonspatial cues, or experience, which are governed by more than one top-down mechanism of attention. However, how the neural mechanisms underlying spatial distractor cues guide proactive suppression of distracting inputs remains unresolved. Here, we recorded electroencephalography signals from 110 subjects in three experiments to identify the role of alpha activity in proactive distractor suppression induced by spatial cues and its influence on subsequent distractor inhibition. Behaviorally, we found novel spatial changes in spatial distractor cues: cueing distractors far away from the target improves search performance for the target while cueing distractors close to the target hampers performance. Crucially, we found dynamic characteristics of spatial representation for distractor suppression during anticipation. This result was further verified by alpha power increased relatively contralateral to the cued distractor. At both the between- and within-subjects levels, we found that these activities further predicted the decrement of subsequent PD component, which was indicative of reduced distractor interference. Moreover, anticipatory alpha activity and its link with subsequent PD component were specific to the high predictive validity of distractor cue. Together, these results provide evidence for the existence of proactive suppression mechanisms of spatial distractors, support the role of alpha activity as gating by proactive suppression and reveal the underlying neural mechanisms by which cueing the spatial distractor may contribute to reduced distractor interference. (235). SignificanceIn space, the attention-capturing distractors are obstacles to successfully identifying targets. How to sidestep task-irrelevant distractors that stand between the target and our focus in advance is essential but still unclear. This research investigated how dynamic spatial cues can help us proactively eliminate attention-capturing distractors. Using three cue-distractor tasks that manipulate the predictive validity of distractor occurrence, we provide a series of evidence for the presence of alpha power activity related to distractor anticipation. Critically, this was the first study linking cue-elicited alpha power and distractor-elicited PD, indicating that spatial modulation of alpha power may reduce distractor interference. These findings delineate the neural mechanisms of proactive suppression for spatial distractors. (109)