Higo Katsuki, Ohtsuka Itsuki, Shimada Sotaro
Organization for the Strategic Coordination of Research and Intellectual Properties, Meiji University, Kanagawa 214-8571, Japan.
Graduate School of Science and Technology, Meiji University, Kanagawa 214-8571, Japan.
eNeuro. 2025 Sep 29;12(9). doi: 10.1523/ENEURO.0587-24.2025. Print 2025 Sep.
The sense of body ownership, a core aspect of self-recognition, has been studied using illusions such as the full-body illusion. Although the premotor cortex is considered central to body ownership in first-person full-body illusions, the occipitotemporal cortex-including the temporoparietal junction (TPJ) and the extrastriate body area (EBA)-also plays a critical role in third-person full-body illusions. However, their distinct contributions to the full-body illusion remain unclear, partly due to the challenges of applying neuroimaging in such experiments. This study employed functional near-infrared spectroscopy to investigate brain activity during a third-person full-body illusion in virtual reality. Eighteen healthy human adult males participated in the study. The experiment consisted of two sessions. In Session 1, participants observed an avatar's back receiving either synchronous or asynchronous visual-tactile stimulation. In Session 2, visual stimuli alone were presented to participants after they experienced the full-body illusion to induce visuotactile discrepancies. In the synchronous condition of Session 1, we found significant deactivation in the superior and middle temporal gyri (partially including the TPJ), followed by higher activity than in the asynchronous condition in the left middle occipital gyrus (likely EBA). The left premotor cortex also showed significant activation (uncorrected), although this did not survive multiple-comparison adjustment. In Session 2, the visuotactile discrepancy induced significant left premotor activation only in the synchronous condition (FDR-corrected). These findings suggest that the occipitotemporal cortex supports receptivity to third-person full-body illusions, whereas the premotor cortex contributes to maintaining illusory body ownership by reconciling multisensory conflicts.
身体所有权感是自我认知的一个核心方面，人们利用诸如全身错觉等幻觉对此进行了研究。尽管在前瞻性全身错觉中，运动前皮层被认为是身体所有权的核心，但枕颞叶皮层，包括颞顶联合区（TPJ）和纹外体区（EBA），在第三人称全身错觉中也起着关键作用。然而，它们对全身错觉的不同贡献仍不清楚，部分原因是在此类实验中应用神经成像存在挑战。本研究采用功能近红外光谱技术，研究虚拟现实中第三人称全身错觉期间的大脑活动。18名健康成年男性参与了该研究。实验包括两个阶段。在第一阶段，参与者观察一个虚拟角色的背部接受同步或异步的视觉-触觉刺激。在第二阶段，在参与者体验了全身错觉后，仅向他们呈现视觉刺激，以诱发视觉-触觉差异。在第一阶段的同步条件下，我们发现颞上回和颞中回（部分包括TPJ）有显著失活，随后左侧枕中回（可能是EBA）的活动高于异步条件。左侧运动前皮层也显示出显著激活（未校正），尽管这在多重比较校正后未保留。在第二阶段，视觉-触觉差异仅在同步条件下诱发了显著的左侧运动前激活（错误发现率校正）。这些发现表明，枕颞叶皮层支持对第三人称全身错觉的感受性，而运动前皮层通过协调多感官冲突，有助于维持虚幻的身体所有权。
