A putative implication for fronto-parietal connectivity in out-of-body experiences.

Self-processing has been related to the prefrontal cortex (PFC) and the temporo-parietal junction (TPJ) as well as to their connectivity. So far, out-of-body experiences (OBEs), impressive transient deviations of intact bodily self-integration, could be associated with the TPJ, but the mediation by the frontal lobe, and thus fronto-parietal connectivity, is yet unknown. Thus, we assessed switching performance to assess fronto-parietal connectivity when healthy participants [11 reported previous OBEs (OBE-individuals); 36 reported no previous OBEs (nOBE-individuals)] performed two different mental own body imagery tasks. By using the same stimuli of a front-facing and back-facing human figure, a cue simultaneously presented with the target indicated to participants whether they had to take the position of the depicted human figure (disembodied self-location mimicking an OBE) or had to imagine that the figure was their own reflection in a mirror (embodied Self-location). By repeating trials of the same task instruction for a differing number of trials (2-6 trials), we could assess switch costs when alternating between these two task instructions with switch costs being considered to be a behavioural indicator of fronto-parietal connectivity. Results showed that OBE-individuals performed worse than nOBE-individuals in switch trials, but not in trials in which the same task instruction was repeated. Moreover, this reduced performance was specific to body positions that are normally considered easier (front-facing in the mirror condition; back-facing in the OBE mimicking condition). These findings suggest that a fronto-parietal network might be implicated in OBEs, and that the flexible and spontaneous egocentric perspective taking of self-congruent body representations is hampered in individuals with previous OBEs.