Are you upset?

Ami Tsuchida and Lesley K. Fellows 
Are You Upset? Distinct Roles for Orbitofrontal and Lateral Prefrontal Cortex in Detecting and Distinguishing Facial Expressions of Emotion
Cereb Cortex 2012 : bhr370v1-bhr370.

Damage to ventromedial PFC impaired the detection of subtle facial expressions of emotion. Such patients had difficulty distinguishing emotional from neutral expressions. In contrast, patients with left ventrolateral PFC were able to detect the presence of emotional signals but had difficulty discriminating between specific emotions. These effects were regionally specific: Dorsomedial prefrontal damage had no effect on either aspect of emotion recognition.