Neural Mechanisms Mediating Contingent Capture of Attention by Affective Stimuli

摘要

Attention is attracted exogenously by physically salient stimuli,nbut this effect can be dampened by endogenous attentionnsettings, a phenomenon called “contingent capture.” Emotionallynsalient stimuli are also thought to exert a strong exogenousninfluence on attention, especially in anxious individuals,nbut whether and how top–down attention can amelioratenbottom–up capture by affective stimuli is currently unknown.nHere, we paired a novel spatial cueing task with fMRI to investigatencontingent capture as a function of the affective saliencenof bottom–up cues (face stimuli) and individual differences inntrait anxiety. In the absence of top–down cues, exogenous stimulinvalidly cueing targets facilitated attention in low-anxiousnparticipants, regardless of affective salience. However, althoughnhigh-anxious participants exhibited similar facilitation followingnneutral exogenous cues, this facilitation was completely absentnfollowing affectively negative exogenous cues. Critically, these effectsnwere contingent on endogenous attentional settings, suchnthat explicit top–down cues presented before the appearance ofnexogenous stimuli removed anxious individualsʼ sensitivity to affectivelynsalient stimuli. fMRI analyses revealed a network of brainnregions underlying this variability in affective contingent capturenacross individuals, including the fusiform face area (FFA), posteriornventrolateral frontal cortex, and SMA. Importantly, activationnin the posterior ventrolateral frontal cortex and the SMA fullynmediated the effects observed in FFA, demonstrating a criticalnrole for these frontal regions in mediating attentional orientingnand interference resolution processes when engaged by affectivelynsalient stimuli.