Prefrontal cortical function and anxiety: controlling attention to threat-related stimuli

Abstract

Threat-related stimuli are strong competitors for attention, particularly in anxious individuals. We used functional magnetic resonance imaging (fMRI) with healthy human volunteers to study how the processing of threat-related distractors is controlled and whether this alters as anxiety levels increase. Our work builds upon prior analyses of the cognitive control functions of lateral prefrontal cortex (lateral PFC) and anterior cingulate cortex (ACC). We found that rostral ACC was strongly activated by infrequent threat-related distractors, consistent with a role for this area in responding to unexpected processing conflict caused by salient emotional stimuli. Participants with higher anxiety levels showed both less rostral ACC activity overall and reduced recruitment of lateral PFC as expectancy of threat-related distractors was established. This supports the proposal that anxiety is associated with reduced top-down control over threat-related distractors. Our results suggest distinct roles for rostral ACC and lateral PFC in governing the processing of task-irrelevant, threat-related stimuli, and indicate reduced recruitment of this circuitry in anxiety.

Common regions of dorsal anterior cingulate and prefrontal–parietal cortices provide attentional control of distracters varying in emotionality and visibility

“…According to one view, while dACC is involved in dealing with non-emotional distraction (as considerable data suggests; e.g., Bush et al 1998;Carter et al 2000), rACC is involved in dealing with emotional distracters (cf. Bishop et al, 2004;Etkin et al, 2006;Whalen et al, 1998). In contrast to this view, in the current study regions of dorsal ACC were identified by the main effects of both visibility and emotionality, though the dACC region identified by the emotional main effect was slightly more posterior than to that identified by the visibility main effect.…”

“…Previous studies investigating the response to emotional distraction have also identified the recruitment of frontal, parietal and cingulate cortex (Bishop et al, 2004;Blair et al, 2007;Etkin et al, 2006;Mitchell et al 2007;Vuilleumier, et al, 2001). However, to our knowledge, no previous work has investigated the effect of distracter visibility on target processing; though related work has shown the increased recruitment of frontal and parietal areas in response to stimuli of increased visual salience (Constantinidis, 2006;Gottlieb et al, 1998;Indovina & Macaluso, 2006).…”

“…In many of the previous studies reporting rACC activation as a response to emotional distraction, the distracters were presented simultaneously with the target stimuli (e.g., Bishop et al, 2004;Etkin et al, 2006;. In addition, several studies indicating a role for rACC adopted a blocked design (Bishop et al, 2004;Whalen et al, 1998) rather than the event related design adopted here (though this is not the case for all studies indicating a role for rACC -Etkin et al, 2006;Vuilleumier et al, 2001). Some studies used ROIs that included only part of dACC (Bishop et al, 2004).…”

“…This issue has been investigated through Stroop-type Bremner et al, 2004;Etkin et al, 2006;Shin et al, 2001;Whalen et al, 1998) and other attentional paradigms (Bishop et al, 2004;Mitchell et al 2007;Simpson et al, 2000;Vuilleumier, et al, 2001). These studies suggest that systems involved in the top-down attentional control of emotional distracters include ACC Bremner et al, 2004;Etkin et al, 2006;Shin et al, 2001;Whalen et al, 1998), PFC (Bishop et al, 2004;Blair et al, 2007;Shin et al, 2001;Simpson et al, 2000;Vuilleumier, et al, 2001;Whalen et al, 1998) and parietal cortex Bremner et al, 2004). However, very little work has addressed if regions providing attentional control of emotional distracters are similar to those responding to other features that increase the salience of the distracter, for example visibility level.…”

“…In particular, it has been argued that attentional control of emotional distracters recruits rACC (Bishop et al, 2004;Etkin et al, 2006;Shin et al, 2001;Vuilleumier et al, 2001;Whalen et al, 1998). In contrast, attentional control of nonemotional distracters is thought to implicate dACC Carter et al 1995Carter et al , 2000Durston et al, 2002;MacDonald et al 2000;Menon et al, 2001).…”