Visuonociceptive facilitation in peripersonal space and its relationship to body ownership.

The feeling that the body belongs to oneself is referred to as the sense of body ownership. Activation of skin nociceptors can contribute to body ownership in a manner similar to tactile input, highlighting multisensory integration between nociception and vision in body ownership. The space surrounding one's own body, termed peripersonal space (PPS), is crucial for interacting with objects, for threat avoidance and self-preservation. While PPS has been extensively studied for touch and vision, less is known about how nociceptive input is processed within PPS and how this relates to body ownership. In two experiments, we investigated whether (1) nociceptive processing shows peripersonal-space-dependent visuonociceptive facilitation (near vs far) and (2) whether this facilitation in perihand space is shaped by changes in body ownership induced by the rubber hand illusion. Participants performed a reaction-time (RT) task responding to painful nociceptive laser stimulation. Experiment 1 showed faster responses when nociceptive stimuli were paired with a visual stimulus presented near rather than far from the body, demonstrating visuonociceptive facilitation within perihand space. Experiment 2 showed faster responses following synchronous than asynchronous visuotactile stimulation, including the predicted advantage for visuonociceptive stimulation near the owned rubber hand. However, this ownership-related facilitation was not selectively confined to near space or to bimodal visuonociceptive stimulation. Together, our findings indicate that nociceptive processing follows PPS-related multisensory principles and is influenced by body ownership. They extend PPS research to the nociceptive domain while indicating that ownership-related facilitation is broader than a selective change in perihand visuonociceptive processing.