Anyone who has watched an episode of “I Survived: Beyond and Back” on the Biography Channel knows that accounts of near death experiences mesmerize the public. They also drive ratings. The typical “I Survived” vignette features someone whose heart has stopped beating and is considered “clinically dead.”
Because everyone who appears on the show is very much alive, there is an obvious gap between clinical death and brain death. The former can herald a still-living twilight world for those who are resuscitated and remember; the latter is final and no one has ever come back to discuss it.
It is this gap period — during which a person may not be breathing or have a pulse — but still has (diminishing) neurological function, that gives rise to the near death experience or NDE. A common feature of many NDEs is the out of body experience, or the sense that the subjective self has left the body and is viewing it as an outsider.
As many recreational drug users and trance dancers know, one need not approach death to have an out of body experience or OBE. Although several drugs can induce such experiences, the tranquilizer ketamine often gives rise to mind-body dissociation or out of body experience. For the spiritually or religiously inclined, out of body experiences are interpreted as proof of the soul. For ketamine users and ravers, neurologically similar experiences are construed as an excellent high.
In a recent study, Canadian psychologists investigated the out of body experiences frequently associated with ketamine use. Leanne Wilkins and colleagues define an OBE as “the experience of discrepancy between the location of one’s subjective sense of ‘self’ and one’s own physical body” and detail three OBE variants: (1) the feeling of separateness, or taking leave of one’s physical body (out of body feeling or OBF), (2) seeing your own body from what seems to be an external viewing station (out of body autoscopy or OBA), and (3) a combination of OBF and OBA.
Out of body experiences “have been associated with various neurological conditions such as epilepsy, migraines, infections and also with psychiatric conditions such as schizophrenia, depression, anxiety, and dissociative disorders.” To this list we might add practices well known to shamans and similar practitioners: dancing, fasting, pain, dreaming, and deprivation.
Regardless of causal mechanism, the authors correctly observe that OBEs “have been an important part of folklore, mythology and spiritual experiences reported across the centuries.” Such experiences, in other words, are put to religious use. With this in mind, the authors assert that ketamine-induced OBEs point to a simpler explanation:
[E]nhanced understanding of cognitive and neural mechanisms of sensory disintegration contributing to the breakdown in the feeling of the integrity of one’s embodiment can legitimize and naturalize the OBEs experienced by neurological patients and those with mental illness and demystify them as ‘‘paranormal’’ and ‘‘anomalous’’ experiences.
This is a circumspect way of saying that OBEs can be caused or induced given certain conditions that affect an important sensory association area in the brain: the Temporo-Parietal Junction (TPJ). This area of the brain is important not only for the integration of external-internal sensations and normal perception of self-embodiment, but also for theory of mind (i.e., attributing mental states to others, whether those others are real or imaginary). It is not surprising, therefore, that lesions or damage to the TPJ often cause out of body experiences. In the Wilkins study, the authors hypothesize that ketamine, which is an NMDA receptor antagonist, similarly disrupts the TPJ and causes out of body experiences.
Because out of body experiences are caused or can be induced under a variety of known conditions, regardless of cultural setting, there is every reason to think that such experiences are brain based. When certain types of experiences are universal, there is nearly always a biological-neurological explanation. What varies in these experiences is how they are patterned and interpreted.
Because these patterns and interpretations vary from culture to culture and religion to religion, it is clear that what one has previously learned (or what one expects or wishes) will condition the experience and its subsequent interpretation. For those who insist on a supernatural explanation, they will have to accept that supernatural experience is not universal, but varies according to culture and religion.
Wilkins, L., Girard, T., & Cheyne, J. (2011). Ketamine as a primary predictor of out-of-body experiences associated with multiple substance use Consciousness and Cognition DOI: 10.1016/j.concog.2011.01.005
Blanke, O. (2005). The Out-of-Body Experience: Disturbed Self-Processing at the Temporo-Parietal Junction The Neuroscientist, 11 (1), 16-24 DOI: 10.1177/1073858404270885
Saxe, R., & Kanwisher, N. (2003). People thinking about thinking people: The role of the temporo-parietal junction in “theory of mind” NeuroImage, 19 (4), 1835-1842 DOI: 10.1016/S1053-8119(03)00230-1