An influential neural model of face perception suggests that the posterior superior temporal sulcus (STS) is sensitive to those aspects of faces that produce transient visual changes, including facial expression. Other researchers note that recognition of expression involves multiple sensory modalities and suggest that the STS also may respond to crossmodal facial signals that change transiently. Indeed, many studies of audiovisual (AV) speech perception show STS involvement in AV speech integration. Here we examine whether these findings extend to AV emotion. We used magnetoencephalography to measure the neural responses of participants as they viewed and heard emotionally congruent fear and minimally congruent neutral face and voice stimuli. We demonstrate significant supra-additive responses (i.e., where AV > [unimodal auditory ؉ unimodal visual]) in the posterior STS within the first 250 ms for emotionally congruent AV stimuli. These findings show a role for the STS in processing crossmodal emotive signals.audio-visual emotion ͉ emotional faces ͉ emotional voices ͉ fear ͉ gamma S ome aspects of faces, such as identity, are relatively fixed whereas other aspects, such as facial expression, can change from moment to moment. A highly influential neural model of face perception suggests that the aspects of faces that change visibly (e.g., eye gaze, lip movement, facial expression) are processed by a neural pathway leading to the posterior superior temporal sulcus (STS) (1, 2). However, both lip movement and facial expression are generally accompanied by changing auditory signals. Indeed, in daily life emotion commonly is conveyed through multiple signals involving the face, voice, and body. Although originating from different sensory modalities, these transient emotive signals are perceived and integrated within our social interactions with seemingly minimal effort. It therefore is possible that recognition of emotional expression is an intrinsically crossmodal process and that the sensitivity of the posterior STS to the changeable aspects of faces may extend to voices, as the posterior STS could serve to integrate emotional signals arising from faces and voices (3). During emotion perception, the role of the posterior STS may extend beyond the visual function of perceiving facial emotion to serve a wider purpose related to the crossmodal integration of facial and vocal signals.The STS is a prime candidate for the integration of visual and auditory emotive signals. The STS lies between primary auditory and visual cortices, and studies of audiovisual (AV) speech integration have demonstrated supra-additive responses in the STS to congruent speech stimuli (4, 5). Supra-additivity is a stringent criterion for multisensory integrative regions and is based on the known electrophysiological behavior of signal integration (6, 7). Supra-additivity occurs when the observed multisensory effect exceeds the sum of the unisensory components, i.e., when AV Ͼ [unimodal auditory (A) ϩ unimodal visual (V)]. The purpose of the pr...