Made you look! Consciously perceived, irrelevant instructional cues can hijack the attentional network.

Functional neuroimaging studies of endogenous cued attention suggest that a fronto-parietal attentional network keeps track of current task objectives in working memory and enhances activity in posterior sensory regions that underlie the perceptual processing of behaviorally relevant stimuli. Relatively little is known, however, about whether consciously perceived, irrelevant instructional cues can hijack the attentional network, leading to an enhancement of the perceptual processing of irrelevant stimuli. Using a cross-modal attentional cueing task in combination with functional magnetic resonance imaging, we found that such irrelevant cues can indeed hijack the attentional network, as indexed by increased activity in (a) frontal regions that control attention and (b) sensory cortices that underlie the perceptual processing of task-irrelevant stimuli. Furthermore, we found that in left ventrolateral (but not dorsolateral) prefrontal regions, the magnitude of this increased activity varies with whether an irrelevant instructional cue is presented simultaneously with (versus after) a relevant instructional cue. These findings show that consciously perceived, irrelevant instructional cues can activate inappropriate task objectives in working memory, resulting in a hijacking of the attentional network. Moreover, they reveal different time courses of hijacking effects in ventrolateral and dorsolateral prefrontal regions, consistent with models in which these regions make distinct contributions to cognitive control.