AUTHOR=Tekgün Ege , Erdeniz Burak 

TITLE=Contributions of Body-Orientation to Mental Ball Dropping Task During Out-of-Body Experiences

JOURNAL=Frontiers in Integrative Neuroscience

VOLUME=Volume 15 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/integrative-neuroscience/articles/10.3389/fnint.2021.781935

DOI=10.3389/fnint.2021.781935

ISSN=1662-5145

ABSTRACT=Out-of-body experiences (OBEs) provide fascinating insights for our understanding of bodily self-consciousness and the workings of the brain. Studies that examined brain lesioned individuals reported that OBEs are generally characterized by participants experiencing themselves outside their physical body (i.e., disembodied feeling) (Blanke and Arzy, 2005). Based on such a characterization, it has been shown possible to create virtual OBEs in immersive virtual environments (Bourdin et al., 2017; Ehrsson, 2007; Ionta et al., 2011). However, the extent to which body-orientation influences the virtual OBEs is not well understood. Thus, in the present study, 30 participants (within group design) experienced a full-body ownership illusion (synchronous visuo-tactile stimulation only) induced with a gender-matched full-body virtual avatar seen from a first-person perspective (1PP). At the beginning of the experiment, participants performed a mental ball dropping task (MBD), seen from the location of their virtual avatar, to provide a baseline measurement. After this, a full-body ownership illusion (embodiment phase) was induced in all participants. This was followed by the virtual OBE illusion phase of the experiment (disembodiment phase) in which the first-person viewpoint was switched to a third-person perspective (3PP), and participants’ disembodied viewpoint was gradually raised to 14 meters above the virtual avatar, from which altitude they repeated the MBD task. During the experiment, this procedure was conducted twice, and the participants were allocated first to the supine or to the standing body position at random. Results of the MBD task showed that participants experienced increased MBD durations during the supine condition compared to the standing condition. Furthermore, although the findings from the subjective reports confirmed previous findings of virtual OBEs, no significant difference between the two postures was found for body ownership. Taken together, the findings of the current study make further contributions to our understanding of both the vestibular system, and of time perception during OBEs.