Department of Information and Management Systems Engineering, Nagaoka University of Technology, Niigata, Japan.
Sci Rep. 2023 Mar 1;13(1):2801. doi: 10.1038/s41598-023-29993-z.
Viewing one's body and even a fake/virtual body experienced as one's own has been suggested to modulate pain perception. However, what happens to pain perception when one's own body part is felt as not belonging to one? We designed a paradigm to induce an illusory feeling of disownership regarding one's limb, investigating whether the feeling affects pain threshold. Participants observed right-side images of their bodies from a third-person perspective via a head-mounted display in real-time. Following instructions, they moved their left hand while keeping their left elbow behind the upper body, so that the connection of their arm to the torso was not visible (test condition), or in front of it, so they could see the arm being part of them (control condition). Then, pain threshold was tested with a thermal stimulator. We found a significantly higher strength of disownership in the test condition than in the control condition. While there was no pain modulation within and between conditions, disownership ratings negatively correlated with pain-threshold changes, where the participants reporting explicit disownership showed lower pain-threshold changes than the others. The finding suggests that while multisensory disintegration had no modulatory effect, the individual sense of disownership was associated with pain perception.
将自身的身体甚至是虚假/虚拟的身体视为自己的身体，已被证明可以调节疼痛感知。然而，当一个人自身的身体部位感觉不属于自己时，疼痛感知会发生什么变化？我们设计了一种范式，通过头戴式显示器从第三人称视角实时观察自己身体的右侧图像，来诱导一种对肢体的虚假所有权丧失感，研究这种感觉是否会影响疼痛阈值。参与者根据指令移动左手，同时将左肘保持在身体后面，使手臂与躯干的连接不可见（测试条件），或者在前面，这样他们就可以看到手臂是他们身体的一部分（对照条件）。然后，用热刺激器测试疼痛阈值。我们发现，在测试条件下，对所有权丧失的感觉明显高于对照条件。虽然在各条件之间没有疼痛调节，但对所有权丧失的评价与疼痛阈值变化呈负相关，即报告明确的所有权丧失的参与者的疼痛阈值变化低于其他人。这一发现表明，尽管多感觉分离没有调节作用，但个体的所有权丧失感与疼痛感知有关。
