Emotional cues during simultaneous face and voice processing: electrophysiological insights

Both facial expression and tone of voice represent key signals of emotional communication but their brain processing
correlates remain unclear. Accordingly, we constructed a novel implicit emotion recognition task consisting of
simultaneously presented human faces and voices with neutral, happy, and angry valence, within the context of
recognizing monkey faces and voices task. To investigate the temporal unfolding of the processing of affective information
from human face-voice pairings, we recorded event-related potentials (ERPs) to these audiovisual test stimuli in 18 normal
healthy subjects; N100, P200, N250, P300 components were observed at electrodes in the frontal-central region, while P100,
N170, P270 were observed at electrodes in the parietal-occipital region. Results indicated a significant audiovisual stimulus
effect on the amplitudes and latencies of components in frontal-central (P200, P300, and N250) but not the parietal occipital
region (P100, N170 and P270). Specifically, P200 and P300 amplitudes were more positive for emotional relative to neutral
audiovisual stimuli, irrespective of valence, whereas N250 amplitude was more negative for neutral relative to emotional
stimuli. No differentiation was observed between angry and happy conditions. The results suggest that the general effect of
emotion on audiovisual processing can emerge as early as 200 msec (P200 peak latency) post stimulus onset, in spite of
implicit affective processing task demands, and that such effect is mainly distributed in the frontal-central region.
This work was supported by a joint PhD student scholarship (2009658022) from China Scholarship Council awarded to T.S.L., a Post-Doctoral Grant
(SFRH/BPD/68967/2010) from Fundação para a Ciência e a Tecnologia - FCT (Portugal) awarded to A.P.P., and by the National Institute of Mental Health - NIMH (RO1 MH 040799 grant awarded to R.W.M.; RO3 MH 078036 grant awarded to M.A.N.).