Amygdala activation to threat under attentional load in individuals with anxiety disorder.

Abstract

Background: Previous studies in healthy subjects have shown that strong attentional distraction prevents the amygdala from responding to threat stimuli. Here, we investigated the effects of attentional load on amygdala activation to threat-related stimuli in individuals suffering from an anxiety disorder.

Methods: During functional magnetic resonance imaging, spider-phobicand healthy control subjects were presented with phobia-related and neutral stimuli while performing a distraction task with varying perceptual load (high vs low).

Results: Our data revealed a pattern of simultaneously increased amygdala and visual cortical activation to threat vs neutral pictures in phobic individuals, compared with controls, occurring regardless of attentional load.

Conclusions: These results suggest that, in contrast to studies in healthy subjects, amygdala activation to clinically relevant threat stimuli is more resistant to attentional load.