Shibuya Satoshi, Ohki Yukari
Department of Integrative Physiology, School of Medicine, Kyorin University, Tokyo, Japan.
Eur J Neurosci. 2025 Mar;61(5):e70035. doi: 10.1111/ejn.70035.
Body ownership-the perception that one's body belongs to oneself-has been explored using a rubber hand illusion, in which individuals misperceive a fake hand as their own (i.e., embodiment of the fake hand) when an unseen real hand and a visible fake hand are stroked synchronously. Thus, the movement of an embodied fake body may be represented in one's own sensorimotor system. Using a combination of the rubber hand illusion and a motor task, we investigated whether simple movement of the embodied fake hand influenced the subsequent movement of the participants' hand. The participants lifted their own index finger immediately upon observing the index finger lifting on the embodied (rubber hand illusion) or non-embodied (non-rubber hand illusion) fake hand (Experiment 1), and a light-emitting diode turning on near the fake hand (Experiment 2). The reaction times, peak velocities, and peak acceleration were extracted from the participants' finger-lifting movements. In Experiment 1, the reaction time was significantly shorter in the rubber hand illusion condition than in the non-rubber hand illusion condition, suggesting the rapid facilitation effect of embodied fake hand movement on actual movement. However, no such motor facilitation was observed in Experiment 2, confirming that the improved reaction time in Experiment 1 resulted from the visual movement of the fake hand rather than attention to the fake hand itself. In contrast to the reaction time, the peak velocity and acceleration did not differ significantly in either experiment. These findings reflect the similar sensorimotor representations of illusory and actual self-movement.
身体所有权——即认为自己的身体属于自己的这种感知——已通过橡胶手错觉进行了探究。在橡胶手错觉实验中，当一只看不见的真实手和一只可见的假手被同步抚摸时，个体就会将假手误认成自己的手（即假手的具身化）。因此，具身化假身体的运动可能会在个体自身的感觉运动系统中得到表征。我们结合橡胶手错觉和一项运动任务，研究了具身化假手的简单运动是否会影响参与者手部随后的运动。在看到具身化（橡胶手错觉）或非具身化（非橡胶手错觉）假手上的食指抬起（实验1），以及假手附近的发光二极管亮起（实验2）后，参与者立即抬起自己的食指。从参与者的手指抬起动作中提取反应时间、峰值速度和峰值加速度。在实验1中，橡胶手错觉条件下的反应时间显著短于非橡胶手错觉条件，这表明具身化假手运动对实际运动具有快速促进作用。然而，在实验2中未观察到这种运动促进作用，这证实了实验1中反应时间的缩短是由假手的视觉运动而非对假手本身的关注导致的。与反应时间不同，在两个实验中峰值速度和加速度均无显著差异。这些发现反映了虚幻的和实际的自我运动在感觉运动表征上的相似性。
