Asymmetrical use of eye information from faces following unilateral amygdala damage

The human amygdalae are involved in processing visual information about the eyes within faces, and play an essential role in the use of information from the eye region of the face in order to judge emotional expressions, as well as in directing gaze to the eyes in conversations with real people. However, the roles played here by the left and right amygdala individually remain unknown. Here we investigated this question by applying the 'Bubbles' method, which asks viewers to discriminate facial emotions from randomly sampled small regions of a face, to 23 neurological participants with focal, unilateral amygdala damage (10 to the right amygdala). We found a statistically significant asymmetry in the use of eye information when comparing those with unilateral left lesions to those with unilateral right lesions, specifically during emotion judgments. The findings have implications for the amygdala's role in emotion recognition and gaze direction during face processing.