P68-T Simultaneous recordings of visual sympathetic skin response (VSSR) and electrical pain SSR in multiple subjects

Background Recently, we measured the autonomous sympathetic skin response (SSR) in the examinator left hand and left foot and in the left hand of a patient with anorgasmia while electrical pain was applied to the examinator. The patient had SSR when he was observing the examinator. In a study addressed to mimicryreactions, happy and angry faces when presented at pre-attentive exposure times (17–40 ms) showed stronger facial EMG in high empathy participants than in low empathy participants (Sonnby-Borgstrom, 2002). We aimed to characterize multiple subjects’ visual sympathetic skin response (VSSR) and electrical pain sympathetic skin response (PSSR) to study the emotional empathic response (EER) and indirectly the face to face social interaction. Methods 7 participants looked to the examinator face when electrical pain stimuluswas applied on his median nerve. Right hand VSSR was compared with the examinator PSSR (control). In one participant we recorded VSSR and facial EMG (left zygomaticus and corrugator supracilii muscles). Inter-subject calibration was performed with sound or Valsalva. Results 3 participants showed VSSR with onset after or simultaneously with the control PSSR at 2-3 s from electrical stimulus, 2 showed reduced amplitude and 1 did not show VSSR. Face surface EMG showed baseline amplitude change in corrugator supracilii. Conclusion As previously stated (Neumann and Westbury, 2011), we observed that VSSR like EER is not present to the same degree in all participants. VSSR and face surface EMG recording might represent a novel technique to assess the autonomic brain responses to human facial pain expression.