Co-existence of two selves: Peripersonal space dynamically remaps around two distinct locations.
Myeong Seop Song, Petr Grivaz, Oliver Alan Kannape, Matthieu Perrenoud, Giulio Rognini, Javier Bello Ruiz, Dario Floreano, Andrea Serino, Olaf Blanke · 2024
Multisensory processing is enhanced for stimuli that appear in close proximity to our body. The so-called peripersonal space (PPS) not only serves as an evolutionary, protective mechanism but also localizes and demarcates our self in space. While our perceived self-location is generally unitary and firmly located at the position of our body, there are rare clinical instances in which patients report the presence of a double (heautoscopy), an actual duplication of the self, and experience themselves to be located simultaneously both in their physical body and in that of the double. Here we used augmented reality and drone technology to create a heautoscopic view of one’s own double: Participants were presented with real-time feedback from a drone-mounted camera that autonomously followed them as they responded to multisensory stimuli on their body and in their environment. Results demonstrate that such manipulation induced a heautoscopy-like state in healthy participants, characterized by two co-existing but spatially distinct PPSs: tactile processing on the body was enhanced by visual stimuli approaching both the participant’s body and, in case of on-going locomotor navigation, the location of their double. While previous studies have shown that PPS remaps towards the location of actions or the perceived self-location, this is the first evidence that PPS can co-exist in two locations.