Results from this study are also consistent with previous fMRI studies neuroimaging studies which demonstrated increased activity of the anterior cingulate and amygdala during the presentation of masked affective faces in healthy control subjects. In an fMRI study of healthy control subjects, Whalen and colleagues (1998) utilized a backward masking paradigm which included masked happy and fearful faces. The authors reported increased activation within the amygdala during masked fearful faces and decreased activity within the amygdala during the viewing of masked happy facial affect. Killgore and Yurgelun-Todd (2004) examined healthy control subjects during a backward masking paradigm which included masked happy and sad faces. Results from that study suggest increased activity within bilateral anterior cingulate gyrus and the amygdala in response to masked happy faces, and increased left anterior cingulate gyral activity in response to masked sad faces. The authors conclude that both the anterior cingulate and amygdala are key regions of the neural network responsible for detecting and discriminating affective information presented below the level of conscious awareness.
