The influence of directed covert attention on emotional face processing

Abstract

Activation of the amygdala and the fusiform face area (FFA) are consistent findings in imaging studies on emotional face processing. There is evidence that these activations occur even when emotional faces are unattended; however, it was also shown that amygdala and FFA activation were modulated by the attentional resources allocated to these stimuli. Attentional resources might thereby not only depend on task demands but also on varying degrees of covert attention processes induced by the task. To address this issue we examined the isolated effect of covert shifts of spatial attention on emotional face processing using functional magnetic resonance imaging during a modified spatial cueing paradigm. Directional spatial and neutral cues were presented superimposed on neutral, happy, sad and fearful faces. Subjects performed a target detection task, while fixation was controlled by simultaneous eye tracking. Reaction times showed a strong cue validity effect across all emotions (i.e., faster responses for directional cues). Comparing directed to nondirected attention revealed a significantly reduced signal in the FFA irrespective of the emotional expression. This effect was also seen in bilateral amygdala, but only in trials including fearful faces. Our findings suggest that covert shifts of attention toward a specific location result in reduced face processing independent from task demands. Furthermore, our data show a task-irrelevant amygdala response specific to fearful faces under a wide attentional focus. Attentional disengagement from the faces led to a suppression of this amygdala response and thus provides further evidence that amygdala activation depends on the focus of attention.