Short communicationAmygdala activation to fearful faces under attentional load

While some functional imaging studies suggested an automatic activation of the amygdala to fearful vs. neutral faces, recent studies showed the absence of amygdala activation to fearful faces under high attentional load induced by distracting tasks. The present fMRI study investigated whether this outcome can be modulated by changing the saliency of the eyes of fearful faces. Subjects had to solve a high perceptual load task while they were presented either with normal faces (Exp. 1) or with normal faces intermixed with faces, in which pupil and iris of eyes were erased to increase the saliency of the normal eyes (Exp. 2). There was no differential amygdala activation to fearful versus neutral faces under standard conditions without any manipulation of the faces (Exp. 1). In contrast to this outcome, Experiment 2 led to differential amygdala activation to the normal but not to the manipulated fearful vs. neutral faces. These findings propose a concept of relative automaticity of the activation of the amygdala. The activation depends on available cognitive resources and on the saliency of specific parts of fearful faces.

► We investigated the activation of the amygdala to fearful faces under high load. ► There was no differential amygdala activation under standard conditions (E1). ► We erased the eyes in half of the faces to increase the normal face saliency (E2). ► There was higher amygdala activation to normal but not to manipulated fearful faces. ► Amygdala activation depends on cognitive resources and saliency of fearful faces.