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

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. 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 perceived 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.

PI: Dr. Robin Bekrater-Bodmann