Synchronous Stimulation With Light and Heat Induces Body Ownership and Reduces Pain Perception

In this study, we investigated whether illusionary body ownership over artificial hands and non-corporeal objects modulates pain perception. Previous research has yielded to mixed results, but has separated painful stimulation used to test pain perception from the stimulation that was used to induce the illusion. Here, we used a variant of the rubber hand illusion (RHI) paradigm and induced the illusion directly via a combination of visual and painful stimuli. We presented heat pain stimuli at the real hand and visual stimuli beneath a rubber hand (part1), or a glass ball (part2). Illusion ratings were higher and pain ratings were lower in the synchronous compared to the asynchronous condition in both parts of the experiment. This study demonstrated the successful induction of a body illusion using a new visual-thermal method with painful stimuli. We showed that the RHI and interestingly also the glass ball has an analgesic effect on the perception of the heat pain stimuli. Our data suggests that induced ownership over artificial limbs but also over non-corporeal objects can reduce the perceived pain perception. This might be mediated via a partial referral of the perceived location of pain or respectively a distribution of pain over 2 locations. PERSPECTIVE: This article presents a new visual-thermal method with painful stimuli for the induction of the Rubber Hand Illusion. An illusionary body ownership over artificial hands and non-corporeal has an analgesic effects on the perception of pain. Similar approaches might be useful to alleviate chronic pain, but needs further testing.