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

我们与身体有着千丝万缕的联系，这是自我体验的一个基本特征。然而，身体和自我的统一是令人惊讶的脆弱。这种脆弱性在截肢者中变得特别明显，他们主要报告持续意识到身体上缺失的身体部位。此外，假肢装置可以恢复被截肢者的身体完整性，有证据表明，可以感觉到对假肢的真实的所有权。有越来越多的证据表明，这些看法涉及广泛分布的额顶叶网络整合身体相关的多感官输入在perpersonal空间。此外，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或不感知假体所有权。阐明潜在的机制可能有助于回答大脑通常如何实现身体和自我之间的感知统一的问题。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，参与者将所有权的感觉从他们的真实的肢体转移到假肢上。基于一项调查，我们试图描述与健康对照组相比，有和没有假肢所有权的截肢者的大队列中扭曲的身体自我体验。在这些参与者的亚组中，我们将使用功能和结构磁共振成像来识别识别与身体所有权体验相关的神经过程以及连接组签名。最后，我们将实验性地扩展近个人空间表征，并将评估假体设备的所有权感觉的相关变化。我们认为这些研究将进一步阐明身体与自我之间统一的神经心理学机制，并最终为治疗身体自我处理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.