Department of Neuroscience, Brain, Body and Self Laboratory, Karolinska Institutet, Sweden.
Department of Neuroscience, Brain, Body and Self Laboratory, Karolinska Institutet, Sweden; Departement of Psychology, University of Amsterdam, the Netherlands.
Cognition. 2021 Jul;212:104722. doi: 10.1016/j.cognition.2021.104722. Epub 2021 Apr 14.
We aimed at investigating the contribution of sensory predictions triggered by the sight of an object moving towards the body for the sense of body ownership. We used a recently developed psychophysical discrimination task to assess body ownership in the rubber hand illusion. In this task, the participants had to choose which of the two right rubber hands in view felt most like their own, and the ownership discriminations were fitted to psychometric curves. In the current study, we occluded the visual impressions of the object moving towards one of the rubber hands (during the first two-thirds of the path) and only revealed the final third of the object's movement trajectory when it touched the rubber hand (approach-occluded condition). Alternatively, we occluded only the final part so that the main part of the movement towards the model hand was visible (touch-occluded). We compared these two conditions to an illusion baseline condition where the object was visible during the entire trajectory and contact (no-occlusion). The touch-occluded condition produced equally strong hand ownership as the baseline condition with no occlusion, while ownership perception was significantly reduced when vision of the object approaching the rubber hand was occluded (approach-occluded). Our results show that tactile predictions generated from seeing an object moving towards the body are temporally exact, and they contribute to the rubber hand illusion by integrating with temporally congruent afferent sensory signals. This finding highlights the importance of multisensory predictions in peripersonal space, object permanence, and the interplay between bottom-up sensory signals and top-down predictions in body ownership.
我们旨在研究因看到物体向身体移动而引发的感觉预测对身体所有权的贡献。我们使用了一种新开发的心理物理辨别任务来评估橡胶手错觉中的身体所有权。在这个任务中，参与者必须选择两个可见的右橡胶手中哪一个感觉最像他们自己的，然后将所有权辨别拟合到心理测量曲线上。在当前的研究中，我们在物体向一个橡胶手移动的前两到三分之一直线中（approach-occluded condition）遮挡了视觉印象，只有当物体触及橡胶手时才显示物体运动轨迹的最后三分之一（touch-occluded condition）。或者，我们只遮挡物体运动的最后一部分，使得模型手的大部分运动是可见的（touch-occluded condition）。我们将这两种情况与物体在整个轨迹和接触期间可见的错觉基线条件（no-occlusion）进行比较。touch-occluded condition 产生的手所有权与无遮挡的基线条件一样强烈，而当遮挡橡胶手的物体接近时，所有权感知明显降低（approach-occluded）。我们的结果表明，从看到物体向身体移动中产生的触觉预测在时间上是准确的，并且通过与时间上一致的传入感觉信号整合，它们有助于橡胶手错觉。这一发现强调了多感觉预测在近体空间、物体永久性以及身体所有权中自上而下的预测与自下而上的感觉信号相互作用的重要性。
