Phantom body: Neuropsychological mechanisms underlying the perceived unity between the body and the self

确信我们与我们的身体密不可分，这是自我体验的一个基本特征。然而，身体和自我的统一令人惊讶地脆弱。这一漏洞在截肢者中变得尤为明显，他们主要报告说，他们正在意识到身体上缺失的幻影部分。此外，假肢装置可以恢复截肢者的身体完整性，而且有证据表明，假肢可以感觉到真正的所有权。越来越多的证据表明，这些知觉涉及一个广泛分布的额顶网络，该网络整合了个人周围空间中与身体相关的多感觉输入。此外，个人周围空间表征的扭曲可能与身体所有权感觉的减少有因果关系。然而，到目前为止，还没有研究直接比较截肢者感知到假体所有权和没有感知到假体所有权。阐明潜在的机制可能有助于回答这样一个问题：大脑通常是如何实现身体和自我之间感知到的统一的。拟议的项目将利用在应用著名的橡胶肢体错觉范例方面取得的进展，在该范例中，参与者将所有权感觉从他们的真实肢体转移到假肢上。基于一项调查，我们试图与健康对照组相比，在拥有和不拥有假肢的大量截肢者队列中描述扭曲的身体自我体验。在这些参与者的分组中，我们将使用功能和结构磁共振成像来识别区分神经过程以及与身体所有权体验相关的连接特征。最后，我们将试验性地扩展个人周围的空间表征，并将评估假肢设备所有权感觉的相关变化。据推测，这些研究将进一步阐明身体与自我统一的神经心理学机制，并最终为治疗身体自我加工障碍的创新治疗方法铺平道路。

The certainty that we are inextricably linked with our body is a fundamental feature of self-experience. Yet, the unity of body and self is surprisingly vulnerable. This vulnerability becomes particularly evident in amputees who predominantly report ongoing awareness of a phantom body part that is physically missing. Moreover, prosthetic devices can restore amputees’ body integrity and there is evidence that real ownership can be perceived for the artificial limb. There is growing evidence indicating that these perceptions involve a widely-distributed fronto-parietal network integrating body-related multisensory input in peripersonal space. Furthermore, distortions of peripersonal space representation might be causally associated with reduced body ownership sensations. However, no study so far has directly compared amputees perceiving or not perceiving prosthesis ownership. Elucidating the underlying mechanisms might help to answer the question how the brain generally accomplish the perceived unity between the body and the self. The proposed project will use the advancements that have made in the application of the well-known rubber limb illusion paradigm in which participants transfer the sensation of ownership from their real limb to an artificial limb. Based on a survey, we seek to characterize distorted bodily self-experiences in large cohorts of amputees with and without prosthesis ownership compared to healthy controls. In subgroups of these participants, we will use functional and structural magnetic resonance imaging to identify discriminating neural processes as well as connectomic signatures associated with body ownership experiences. Finally, we will experimentally extend peripersonal space representation, and will assess associated changes in ownership sensations for the prosthetic device. It is assumed that these studies will further elucidate the neuropsychological mechanisms underlying the unity between the body and the self and will eventually pave the way for innovative therapeutic approaches for the treatment of disturbed bodily self-processing.