Responsibility modulates pain-matrix activation elicited by the expressions of others in pain

- Responsibility modulates empathy related brain responses.
- Being fully responsible for another's pain increases activity in the witness' pain-matrix.
- Sharing responsibility or not being responsible reduces pain-matrix activity.

Here we examine whether brain responses to dynamic facial expressions of pain are influenced by our responsibility for the observed pain. Participants played a flanker task with a confederate. Whenever either erred, the confederate was seen to receive a noxious shock. Using functional magnetic resonance imaging, we found that regions of the functionally localized pain-matrix of the participants (the anterior insula in particular) were activated most strongly when seeing the confederate receive a noxious shock when only the participant had erred (and hence had full responsibility). When both or only the confederate had erred (i.e. participant's shared or no responsibility), significantly weaker vicarious pain-matrix activations were measured.

Summary figure: (A) Participants believed to perform a flanker task in the scanner, while FC, supposedly another participant, was doing the same task, at the same time, in another room. For each trial, the performances of FC and participant were shown to both. Whenever either or both erred, FC received a noxious shock, and the participant saw her reaction through a CCTV feed (B top). If both performed correctly, an innoxious shock was delivered (B bottom). Brain activation measured in the participant while watching the painful CCTV feed was stronger when only the participant had erred, and therefore had full responsibility for the shock compared to conditions in which both had erred, and responsibility was shared (C). A pain localizer in which the participant received electroshocks and evaluated how unpleasant they were revealed regions involved in experiencing the unpleasantness of pain (D). Importantly, some of the regions in which responsibility influenced brain activity to the video overlapped with the pain localizer (yellow in E, including ACC and Insula), supporting that affective other-pain processing is reduced if responsibility for that pain is shared.190