Freethought & Rationalism Archive

ps418 · 12-02-2002, 02:24 PM

Are out-of-body experiences really evidence that mind is seperable from the body? Or are they simply a novel type of hallucination? Whether it is really possible to leave the body or not, it is clear that hallucinatory experiences of leaving the body can be induced by altering the brain in certain ways.

As discussed in a recent thread, drugs are by far the most reliable way to induce an OOBE, particularly the dissociative anaethestic ketamine (e.g. <a href="http://leda.lycaeum.org/Documents/The_Ketamine_Model_of_the_Near_Death_Experience.92 64.shtml" target="_blank">Jansen, 2000</a>).

It has also been shown that the sensation of 'leaving one's body' can be induced by electrical stimulation of the brain. Wilder Penfield conducted many electrical stimulation experiments, and induced many phenomena, such as vivid visual memories, music, tastes, and so on. One patient exclaimed "Oh god, I am leaving my body" following stimulation of a point on her temporal lobe (Journal of Mental Science 101 451-465, 1955, p. 458).

Recently this phenomenon was reproduced, briefly but repeatedly, in a 43 year old woman, by electrical stimulation of her right angular gyrus. The woman reported seeing herself from above. The stimulation also produced strong vestibular/somatosensory hallucinations -- feelings of falling from a great height, lightness, or floating/levitation. (kind of like when you wake up with a start, feeling as if you're falling out of bed)

Quote:

'Out-of-body' experiences (OBEs) are curious, usually brief sensations in which a person's consciousness seems to become detached from the body and take up a remote viewing position. Here we describe the repeated induction of this experience by focal electrical stimulation of the brain's right angular gyrus in a patient who was undergoing evaluation for epilepsy treatment. Stimulation at this site also elicited illusory transformations of the patient's arm and legs (complex somatosensory responses) and whole-body displacements (vestibular responses), indicating that out-of-body experiences may reflect a failure by the brain to integrate complex somatosensory and vestibular information.

Blanke et al., 2002. Neuropsychology: Stimulating illusory own-body perceptions. Nature 419, 269 - 270

[ December 02, 2002: Message edited by: ps418 ]

Shadownought · 12-02-2002, 05:39 PM

Quote:

Recently this phenomenon was reproduced, briefly but repeatedly, in a 43 year old woman, by electrical stimulation of her right angular gyrus. The woman reported seeing herself from above.

That would be an incredibly strange experience...
*zap* Hey, I see the top of my head!

Pretty nifty discovery, if you ask me.

[ December 02, 2002: Message edited by: Shadownought ]

winstonjen · 12-02-2002, 05:44 PM

I agree, Shadownought. Also, how can they tell whether the vision they saw is the result of a dream (which can echo human experience), a hallucination, or a vision from God or Satan?

Defiant Heretic · 12-02-2002, 10:01 PM

Related information: Studies have shown that when the brain is deprived of oxygen, the subject experiences something similar to a "near death experience", generally a bright light at the end of a tunnel.
I don�t know how closely this is tied to an "out of body experience".

winstonjen · 12-02-2002, 10:19 PM

Quote:

Originally posted by Defiant Heretic:
Related information: Studies have shown that when the brain is deprived of oxygen, the subject experiences something similar to a "near death experience", generally a bright light at the end of a tunnel.
I don�t know how closely this is tied to an "out of body experience".

I think that hallucinations occur when the brain is deprived of oxygen.

ps418 · 12-04-2002, 03:13 PM

Quote:

Originally posted by Shadownought:

That would be an incredibly strange experience...
*zap* Hey, I see the top of my head!

Pretty nifty discovery, if you ask me.

[ December 02, 2002: Message edited by: Shadownought ]

Actually, the woman reported seeing herself from above, but said she could only see her legs and trunk. It is unclear from the article what else she 'saw.' There are many descriptions of OOBEs induced by temporal lobe seizures and drugs in which the entire scene is seen and described from a bird's eye perspective (just like dreams often are experienced from a bird's eye perspective). I dont know if this is what was happening here, or if it was only the somathestic sensation of floating out of her body.

Also, the researchers repeated the stimulation on nearby cortical areas. In one case, they had her hold her hand out in front of her face. Upon stimulation, she moved her head, and said she saw her hand approaching her face very quickly. Same thing with her legs. Her legs were bent at the knee, so that she could see her knees in front of her. Again, her knees appeared to fly towards her face.

[ December 05, 2002: Message edited by: ps418 ]

ps418 · 12-04-2002, 03:16 PM

Quote:

Originally posted by Defiant Heretic:
Related information: Studies have shown that when the brain is deprived of oxygen, the subject experiences something similar to a "near death experience", generally a bright light at the end of a tunnel.
I don�t know how closely this is tied to an "out of body experience".

The light and the tunnel are evoked by many different conditions. Anoxia is one condition, but far from the only one, and is not itself a necessary condition.

ps418 · 12-05-2002, 06:11 AM

In addition to drugs and direct electrical stimulation, out-of-body experiences are often induced by seizures having a focus in the temporal lobe. Patients who have temporal lobe epilepsy often report OOBEs (along with religious visions, deja vu, and other phenomena), and often manifest hypereligiosity.

Devinksy reportes that in 21 patients with a known seizure focus who experienced autoscopia or OOBEs associated with seizures, 18 had a seizure focus in the temporal lobe.

Quote:

We report the cases of 10 patients with seizures and autoscopic phenomena, which include seeing one's double and out-of-body experiences, and review 33 additional cases of autoscopic seizures from the literature. Autoscopic phenomena may be symptoms of simple partial, complex partial, or generalized tonoclonic seizures. Autoscopic seizures may be more common than is recognized; we found a 6.3% incidence in the patients we interviewed. The temporal lobe was involved in 18 (86%) of the 21 patients in whom the seizure focus could be identified. There was no clear lateralization of lesions in patients with ictal autoscopy. The response of autoscopic episodes to treatment usually paralleled that of the underlying seizure disorder. Autoscopic phenomena are likely to be discovered only on specific questioning of patients with epilepsy and may be an important, distressing feature of a chronic seizure disorder.

Devinsky O, Feldmann E, Burrowes K, Bromfield E., Autoscopic phenomena with seizures. Arch Neurol 1989 Oct;46(10):1080-8.

Quote:

We report a 38 year-old patient who had temporoparietal epilepsy and unusual ictal "out of body" experiences that remained undiagnosed for more than ten years, until her admission for a motor seizure of the left hemibody. Out of body episodes were experienced as intense and ecstatic astral journeys. EEG showed a bilateral extension of epileptiform abnormalities to the parietal regions, predominantly on the right side. We discuss the various forms of heautoscopy and their putative mechanisms. We suggest that a disturbance in representing space in independent extrapersonal and personal coordinates might be as crucial as the elusive hypothesis of a body schema disorder. Combined involvement of the parietal neocortex and temporolimbic structures might allow those experiences to gain a subjective vividness which appears to be indissociable from normal conscious experiences.

Vuilleumier P, Despland PA, Assal G, Regli F.,Astral and out-of-body voyages. Heautoscopy, ecstasis and experimental hallucinations of epileptic origin. Rev Neurol (Paris) 1997 Mar;153(2):115-9

Also, here is the Nature science update article describing the paper by Blanke et al, discussed in the OP:

<a href="http://www.nature.com/nsu/020916/020916-8.html" target="_blank">Electrodes trigger out-of-body experience</a>

ps418 · 12-09-2002, 01:53 PM

One more point on the OOBEs -- they are not nearly as common in people who nearly die as many people have been led to believe. I've now looked at two prospective studies elucidating the prevalence of NDEs, van Lommel et al (Lancet 2001; 358: 2039-45), and Parnia et al. (Resuscitation 2001; 48: 149-56).

In both studies --the only two prospective studies of the NDE, as far as I know-- the vast majority of survivors, about 90%, experienced nothing resembling the classic NDE. In van Lommel et al (2001), 41/344 experienced a core NDE, as defined by Ring's weighted core index. And the authors state that this may be an overestimate. In Parnia et al. (2001), 4/63 (6.3%) of cardiac arrest survivors reported some form of NDE, assessed using the Greyson NDE scale.

In van Lommel et al, only 15/344 cardiac arrest survivors were postive for "out of body experience," but it is unclear what was counted as a postive. For instance, if the patient said "I lost awareness of my body," or "It was like I did not have a body," was that counted as a positive? Parnia et al's prospective study found 0 out of body experiences. None of the 4 patients who experienced NDEs experienced an out of body experience. Which is a shame, because the researchers had place hidden targets that could be seen from the perspective of the ceiling -- as a test of veridical out of body perception.

[ December 09, 2002: Message edited by: ps418 ]

[ December 09, 2002: Message edited by: ps418 ]

sourdough · 12-14-2002, 06:07 PM

I think NDE out of body exp is all in the brain,much like a dream,
how could anyone see their body,being outside of it,as a soul/spirit whatever,without physical eyes???

12-09-2002, 01:53 PM	#9
ps418 Veteran Member Join Date: Mar 2001 Location: Louisville, KY, USA Posts: 1,840	One more point on the OOBEs -- they are not nearly as common in people who nearly die as many people have been led to believe. I've now looked at two prospective studies elucidating the prevalence of NDEs, van Lommel et al (Lancet 2001; 358: 2039-45), and Parnia et al. (Resuscitation 2001; 48: 149-56). In both studies --the only two prospective studies of the NDE, as far as I know-- the vast majority of survivors, about 90%, experienced nothing resembling the classic NDE. In van Lommel et al (2001), 41/344 experienced a core NDE, as defined by Ring's weighted core index. And the authors state that this may be an overestimate. In Parnia et al. (2001), 4/63 (6.3%) of cardiac arrest survivors reported some form of NDE, assessed using the Greyson NDE scale. In van Lommel et al, only 15/344 cardiac arrest survivors were postive for "out of body experience," but it is unclear what was counted as a postive. For instance, if the patient said "I lost awareness of my body," or "It was like I did not have a body," was that counted as a positive? Parnia et al's prospective study found 0 out of body experiences. None of the 4 patients who experienced NDEs experienced an out of body experience. Which is a shame, because the researchers had place hidden targets that could be seen from the perspective of the ceiling -- as a test of veridical out of body perception. [ December 09, 2002: Message edited by: ps418 ] [ December 09, 2002: Message edited by: ps418 ]</p>

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12-02-2002, 05:44 PM	#3
winstonjen Veteran Member Join Date: Nov 2002 Location: Brisbane, Australia Posts: 3,425	I agree, Shadownought. Also, how can they tell whether the vision they saw is the result of a dream (which can echo human experience), a hallucination, or a vision from God or Satan?

12-02-2002, 10:01 PM	#4
Defiant Heretic Veteran Member Join Date: Jul 2002 Posts: 1,288	Related information: Studies have shown that when the brain is deprived of oxygen, the subject experiences something similar to a "near death experience", generally a bright light at the end of a tunnel. I don�t know how closely this is tied to an "out of body experience".

12-14-2002, 06:07 PM	#10
sourdough Veteran Member Join Date: Nov 2002 Location: one nation under-educated Posts: 1,233	I think NDE out of body exp is all in the brain,much like a dream, how could anyone see their body,being outside of it,as a soul/spirit whatever,without physical eyes???

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