Deficient mental own-body imagery in a neurological patient with out-of-body experiences due to cannabis use

Abstract

Mental imagery Body Drug use a b s t r a c tIn the present work, we report repeated out-of-body experiences (OBEs) in a patient with tetraplegia and severe somatosensory loss due to multiple sclerosis and predominant involvement of the cervical spinal cord. OBEs were experienced on a daily basis and induced by cannabis treatment that was started for severe spasticity with painful cramps and cloni.In order to investigate the link between OBEs and mental own-body imagery, the patient was asked to imagine himself in the position and visual perspective that is generally reported during OBEs, using front-and back-facing schematic human stimuli. Performance was measured before and after cannabis consumption. First, our data reveal that the patient was less accurate for back-facing than front-facing stimuli. This was found before and after cannabis consumption and is the opposite pattern to what is generally observed in healthy participants and in our control subjects (who did not use cannabis). We refer to this as lesion effect and argue that this relative facilitation for stimuli reflecting the position and visual perspective that is generally reported during OBEs might be due to recurrent and spontaneous own-body transformations during the patient's frequent OBEs. Secondly, we found a cannabis effect, namely a performance improvement in the back-facing condition while performance in the front-facing condition remained unchanged, after cannabis administration. We argue that cannabis administration may interfere with own-body imagery when reflecting the actual body position and only when associated with brain damage. Based on these data we propose an extended neurological model for own-body illusions including multisensory and sensorimotor mechanisms, cannabis consumption, and cortical and subcortical processing.

Anomalous bodily-self experiences among recreational ketamine users

“…Although rates of out-of-body experiences were lower in our polydrug sample, they were still higher than those found in normative groups (e.g., Braithwaite et al, 2010;Easton et al, 2009). In this regard, we note that cannabis use has also been linked to out-of-body phenomena (e.g., Overney et al, 2009;Wilkins et al, 2011); moreover, 99% of the current sample reported lifetime use of cannabis, most of whom reported very frequent use (see Wilkins et al, 2011, for more a more complete breakdown of drug use in the overall sample). Future exploration of interactions among the various neurochemical systems affected by these drugs, differential effects of acute and chronic exposure, and their relations to gross neuroanatomical features, on susceptibility to anomalous and psychotic experiences is also warranted (Corlett, Frith, & Fletcher, 2009).…”

“…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.…”

Deliberate and spontaneous sensations of disembodiment: capacity or flaw?

“…We have reviewed behavioural and neuroimaging studies suggesting that the brain processes involved in the deliberate mental transformation of one's own body may be the same as those implicated in perspective taking (for review see Kessler & Wang, 2012;Kessler & Thomson, 2010;Kessler & Rutherford, 2010;van Elk & Blanke, 2013;Popescu & Wexler, 2012) and it was suggested that this provides a logical link to OBE. This is echoed by the relevant literature on OBE (Arzy et al, 2006;Blackmore, 1982;Olaf Blanke & Arzy, 2005;Brugger, 2002;Cook & Irwin, 1983;Easton et al, 2009;Mohr, Blanke, & Brugger, 2006;Overney, Arzy, & Blanke, 2009), yet, only a handful of these studies actually explored performance on a perspective taking task in direct relation to samples reporting OBEs -and these have produced mixed results Easton et al, 2009).…”

Fractionating the unitary notion of dissociation: disembodied but not embodied dissociative experiences are associated with exocentric perspective-taking

“…In addition, behavioral studies have argued that the brain processes involved in the mental transformation of one’s own body may be the same as those implicated in the computation of an exocentric perspective (for review, see Kessler and Rutherford, 2010; Kessler and Thomson, 2010; Kessler and Wang, 2012; Popescu and Wexler, 2012; van Elk and Blanke, 2013) and particularly in the OBE (Cook and Irwin, 1983; Blackmore, 1987; Brugger, 2002; Blanke and Arzy, 2005; Blanke et al, 2005; Arzy et al, 2006; Mohr et al, 2006; Easton et al, 2009; Overney et al, 2009; Braithwaite et al, 2011). Most of the latter studies used performance at the “own-body-transformation” (OBT) task to explore perspective-taking and have implicated the temporal–parietal junction in the mental transformation of one’s own body and perspective (see Blanke et al, 2005).…”