Studies of individuals with affective disorders that have used masked paradigms also report activity within anterior cingulate and amygdalar regions. Sheline et al. (2001) used a backwad masking paradigm to examine depressed subjects prior to and following a course of antidepressant treatment and compared their activation levels to healthy control subjects. At baseline, prior to treatment, depressed subjects demonstrated exaggerated left amygdalar activity relative to control subjects for masked happy and fearful faces, which was greatest for masked fearful faces. Following antidepressant treatment, bilateral activation within the amygdala was reduced or “normalized” relative to baseline levels for both facial affect types. The authors conclude that even when presented below conscious awareness, depressed subjects demonstrate a hyperarousal of the amygdala in response to masked facial affect. Results from these investigations underscore the importance of the anterior cingulate and amygdala in affective processing, even when the stimuli is not consciously perceived by the individual. These data are also consistent with other investigations, suggesting that the anterior cingulate serves an indirect function by integrating emotional and attentional processing, and that the amygdala is
