Esteves Daniela, Valente Madalena, Bendor Shay Englander, Andrade Alexandre, Vourvopoulos Athanasios
Institute for Systems and Robotics (ISR-Lisboa), Bioengineering Department, Instituto Superior Técnico, Lisbon, Portugal.
Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal.
Front Neuroergon. 2025 May 12;6:1572851. doi: 10.3389/fnrgo.2025.1572851. eCollection 2025.
The Sense of Embodiment (SoE) refers to the subjective experience of perceiving a non-biological body part as one's own. Virtual Reality (VR) provides a powerful platform to manipulate SoE, making it a crucial factor in immersive human-computer interaction. This becomes particularly relevant in Electroencephalography (EEG)-based Brain-Computer Interfaces (BCIs), especially motor imagery (MI)-BCIs, which harness brain activity to enable users to control virtual avatars in a self-paced manner. In such systems, a strong SoE can significantly enhance user engagement, control accuracy, and the overall effectiveness of the interface. However, SoE assessment remains largely subjective, relying on questionnaires, as no definitive EEG biomarkers have been established. Additionally, methodological inconsistencies across studies introduce biases that hinder biomarker identification. This study aimed to identify EEG-based SoE biomarkers by analyzing frequency band changes in a combined dataset of 41 participants under standardized experimental conditions. Participants underwent virtual SoE induction and disruption using multisensory triggers, with a validated questionnaire confirming the illusion. Results revealed a significant increase in Beta and Gamma power over the occipital lobe, suggesting these as potential EEG biomarkers for SoE. The findings underscore the occipital lobe's role in multisensory integration and sensorimotor synchronization, supporting the theoretical framework of SoE. However, no single frequency band or brain region fully explains SoE. Instead, it emerges as a complex, dynamic process evolving across time, frequency, and spatial domains, necessitating a comprehensive approach that considers interactions across multiple neural networks.
身体归属感（SoE）指的是将非生物身体部位感知为自身的主观体验。虚拟现实（VR）提供了一个强大的平台来操控身体归属感，使其成为沉浸式人机交互中的一个关键因素。这在基于脑电图（EEG）的脑机接口（BCI）中，尤其是运动想象（MI）-BCI中变得尤为重要，运动想象脑机接口利用大脑活动让用户能够自主控制虚拟化身。在这样的系统中，强烈的身体归属感可以显著提高用户参与度、控制准确性以及接口的整体有效性。然而，身体归属感的评估在很大程度上仍然是主观的，依赖于问卷调查，因为尚未确定明确的脑电图生物标志物。此外，各研究之间的方法不一致会引入偏差，阻碍生物标志物的识别。本研究旨在通过分析41名参与者在标准化实验条件下的组合数据集中的频段变化来识别基于脑电图的身体归属感生物标志物。参与者使用多感官触发器进行虚拟身体归属感诱导和干扰，一份经过验证的问卷证实了这种错觉。结果显示枕叶的β波和γ波功率显著增加，表明这些可能是身体归属感的脑电图生物标志物。这些发现强调了枕叶在多感官整合和感觉运动同步中的作用，支持了身体归属感的理论框架。然而，没有单一的频段或脑区能够完全解释身体归属感。相反，它是一个在时间、频率和空间域中不断演变的复杂动态过程，需要一种综合的方法来考虑多个神经网络之间的相互作用。
