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

Abstract

AutoscopyParanormal experience a b s t r a c t 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 Selflocation). 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 frontoparietal connectivity. Results showed that OBE-individuals performed worse than nOBEindividuals 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. ª 2008 Elsevier Srl. All rights reserved. IntroductionIntact self representation relies on the ability to experience oneself as an enduring and spatial entity (i.e., the feeling that we are the same person across time and space) to which certain mental events and actions are ascribed (i.e., the feeling of agency; being author of one's own thoughts and actions) and which is distinct from the environment (e.g., Blanke et al., 2005;Brugger et al., 1997;Frith, 2005;Halligan, 2002;Kircher and David, 2003;Ramachandran and Hirstein, 1998 for recent accounts). More recent philosophical and neurological theories have also highlighted the relevance of the bodily self, i.e., * Corresponding author. Department of Experimental Psychology, University of Bristol, 12a Priory Road, Bristol BS8 1TU, UK. E-mail address: christine.mohr@bristol.ac.uk (C. Mohr).a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c o r t e x 0010-9452/$ -see front matter ª

Mental Imagery of Self-Location during Spontaneous and Active Self–Other Interactions: An Electrical Neuroimaging Study

“…This may underline that mental body transformation in back orientation is the most difficult of all tested body transformations, in accordance with previous work (Arzy et al, 2006;Mohr et al, 2006;Easton et al, 2009). We therefore suggest that we were not able to distinguish SPO/ OBT from MIR task related to brain activations in the back orientation because, in the MIR task, the performance was more variable and several participants actually performed OBT transformations.…”

“…This was also reflected in the EP data because MIR, OBT, and SPO tasks were associated with the same brain activation. The back orientation is the condition with highest difficulty (Arzy et al, 2006;Mohr et al, 2006;Easton et al, 2009), and may also be character- Figure 5. Differential source localizations between SPO/OBT tasks versus MIR task activations at 517-628 ms PSO.…”

Anomalous bodily-self experiences among recreational ketamine users

“…However, different aetiologies may lead to similar disintegration of vestibular and sensorimotor processes (e.g., Overney, Arzy, & Blanke, 2009). Recent behavioural data also supports proposals of temporal-lobe instability and abnormal frontal-parietal connectivity (Easton, Blanke, & Mohr, 2009) in relation to out-of-body experiences.…”

“…However, given the heterogeneity of individual experiences and numerous conditions (including normative samples) associated with out-of-body phenomena (Braithwaite & Dent, 2011;Easton et al, 2009), it remains an empirical question the extent to which the phenomenological structure and neurobiological mechanisms generalise across different aetiologies of out-of-body experiences. In this regard, the current study extends our investigation of the relations among the previously discussed phenomena in a unique sample of recreational ketamine users and other polydrug users.…”

On the relation between spontaneous perspective taking and other visuospatial processes

“…A particularly interesting study that highlights the close connection between IPT and SPT is that by Easton, Blanke, and Mohr (2009). In their study, participants with prior outof-body experiences and thus, arguably, nonstandard SPT behavior performed worse when explicitly asked to switch between either imagining themselves in the position of someone else (IPT) or imagining the other person as being a reflection of themselves in a mirror.…”