gasp@bu-cs.BU.EDU (Isaac Kohane) (11/07/86)
From: AJDC Vol.140 p 1110 (Nov. 86) The article reports the results of interviews with 11 patients aged 3 through 16, who had survived critical illnesses, including cardiac arrest and profound coma. The salient and shared aspects of the children's NDE's: 1) feeling of being out of body 2) seeing physical body from "above" 3) perception of darkness 4) travelling in a tunnel 5) return to body Apparently, the difference between these childhood NDE's and their adult counterparts is the concrete nature and the relative lack of narrative detail of the former with respect to the latter. The article also goes into some detail as to a possible pathophysiology for NDE's. "Within the temporal lobe there are neuronal connections that, when electrically stimulated, produce the sensation of being outside the physical body. For example, a 33 year old man suffered from temporal lobe seizures that produced hallucinations of seeing himself. On electrical stimulation within the fissure of Sylvius [adjacent to the temporal lobe] the patient exclaimed `Oh God, I am leaving my body.'... The area of the temporal lobe is connected by serotoninergic neurons to the midbrain raphe. Psychological stress and psychoactive drugs such as LSD and ketamine have a neurochemical effect in the latter part of the brain that is mediated by serotonin. We speculate that hypercapnia or hypoxia could also trigger NDE-like experiences through direct activation of the temporal lobe or indirectly through an effect in the midbrain [they refer to a figure that diagrams midbrain temporal lobe connections]. We present this model as a first neurophysiological attempt to analyze NDEs." They could be wrong, but it's an interesting hypothesis.
dcohen@topaz.RUTGERS.EDU ( ) (11/10/86)
In article <2303@bucse.bu-cs.BU.EDU>, gasp@bu-cs.BU.EDU (Isaac Kohane) writes: > From: AJDC Vol.140 p 1110 (Nov. 86) > The article also goes into some detail as to a possible pathophysiology > for NDE's. "Within the temporal lobe there are neuronal connections that, > when electrically stimulated, produce the sensation of being outside the > physical body. For example, a 33 year old man suffered from temporal lobe > seizures that produced hallucinations of seeing himself. On electrical > stimulation within the fissure of Sylvius [adjacent to the temporal lobe] > the patient exclaimed `Oh God, I am leaving my body.'... The area of the > temporal lobe is connected by serotoninergic neurons to the midbrain raphe. > Psychological stress and psychoactive drugs such as LSD and ketamine have > a neurochemical effect in the latter part of the brain that is mediated by > serotonin. We speculate that hypercapnia or hypoxia could also trigger > NDE-like experiences through direct activation of the temporal lobe > or indirectly through an effect in the midbrain [they refer to a figure > that diagrams midbrain temporal lobe connections]. We present this model > as a first neurophysiological attempt to analyze NDEs." This is probably the most sensible explanation of NDE's I've seen yet. The only thing that puzzles me about it is that I can't think of a good evolutionary advantage to having this neuronal structure around. Why should it be useful to devote a chunk of brain circuitry to creating hallucinations of leaving the body? Please don't answer that not every natural phenomenon has evolutionary advantages! Most of 'em do, and besides it would probably be a DISadvantage to keep around brain tissue not meant to be used at some point or other. -- Have Fun! --Dawn (dcohen@topaz.rutgers.edu)
andrea@hp-sdd.HP.COM (Andrea K. Frankel) (11/12/86)
In article <6931@topaz.RUTGERS.EDU> dcohen@topaz.RUTGERS.EDU ( ) writes: > This is probably the most sensible explanation of NDE's I've seen >yet. The only thing that puzzles me about it is that I can't think of >a good evolutionary advantage to having this neuronal structure >around. Why should it be useful to devote a chunk of brain circuitry >to creating hallucinations of leaving the body? I just finished "Using Your Brain, For a Change" - the latest NLP refinement - and it seems that one of the most significant ways you can decrease the emotional impact of a memory is to change it from associative to dissociative. (Associative = reliving it through your own eyes, from the vantage point you had; dissociative = seeing yourself in the memory, as if from an outside viewpoint.) And vice versa: you can make a memory more significant emotionally by changing from dissociative to associative. The book had many anecdotes about helping depressives, who seem to have about the same number of happy and sad memories as non-depressives, but who have all or most of the happy ones dissociated and the unhappy ones associated! (Clearly, you want it the other way around.) So for an off-the-wall guess extrapolated from the above, our caveman ancestors may have been able to deal with intense pain (such as being gored during a hunt) or other acute unpleasantness by dissociating immediately, even during the experience if possible. It worked for me while getting a wisdom tooth pulled (I was able to get by with less anesthesia than I usually need). So there may be some survival value lurking in there after all. Andrea Frankel, Hewlett-Packard (San Diego Division) (619) 592-4664 "every time that wheel goes round, bound to cover just a little more ground" ______________________________________________________________________________ UUCP : {hplabs|hp-pcd|hpfcla|hpda|noscvax|gould9|sdcsvax}!hp-sdd!andrea UUCP : {cbosgd|allegra|decvax|gatech|sun|tektronix}!hplabs!hp-sdd!andrea ARPA : hp-sdd!andrea@nosc.arpa CSNET : hp-sdd!andrea@hplabs.csnet USnail: 16399 W. Bernardo Drive, San Diego CA 92127-1899 USA
levy@ttrdc.UUCP (Daniel R. Levy) (11/12/86)
In article <6931@topaz.RUTGERS.EDU>, dcohen@topaz.RUTGERS.EDU (dawn) writes: >> From: AJDC Vol.140 p 1110 (Nov. 86) > >> The article also goes into some detail as to a possible pathophysiology >> for NDE's. "Within the temporal lobe there are neuronal connections that, >> when electrically stimulated, produce the sensation of being outside the >> physical body.... >> We present this model >> as a first neurophysiological attempt to analyze NDEs." > > This is probably the most sensible explanation of NDE's I've seen >yet. The only thing that puzzles me about it is that I can't think of >a good evolutionary advantage to having this neuronal structure >around. Why should it be useful to devote a chunk of brain circuitry >to creating hallucinations of leaving the body? > > Please don't answer that not every natural phenomenon has >evolutionary advantages! Most of 'em do, and besides it would >probably be a DISadvantage to keep around brain tissue not meant to >be used at some point or other. Gee, you have just argued against the existence of the appendix :-). Also, the artificial electrical stimulation of a brain region might be a coarse-resolution event, affecting a large region of cells where normal function might only involve only a few, separated cells in the region. It's as if you shorted out an entire RAM chip in an operating computer to see what that part of memory was being used for. What I wonder, however, is whether the induced out-of-body "hallucinations" referred to in the original article might not still BE the "real thing"? The article didn't say whether the subject was then asked whether he could "see" things (like objects on a shelf overhead or in another room) which would be possible to see if it were really an out-of-body experience. -- ------------------------------- Disclaimer: The views contained herein are | dan levy | yvel nad | my own and are not at all those of my em- | an engihacker @ | ployer or the administrator of any computer | at&t computer systems division | upon which I may hack. | skokie, illinois | -------------------------------- Path: ..!{akgua,homxb,ihnp4,ltuxa,mvuxa, go for it! allegra,ulysses,vax135}!ttrdc!levy
osbook@sdcsvax.UCSD.EDU (osbook) (11/25/86)
In article <6931@topaz.RUTGERS.EDU> dcohen@topaz.RUTGERS.EDU ( ) writes: >In article <2303@bucse.bu-cs.BU.EDU>, gasp@bu-cs.BU.EDU (Isaac Kohane) writes: >> From: AJDC Vol.140 p 1110 (Nov. 86) >> quote from an article.. "...electrically stimulated, produce >> the sensation of being outside the physical body...." ... > This is probably the most sensible explanation of NDE's I've seen > yet. The only thing that puzzles me about it is ... Why should > it be useful to devote a chunk of brain circuitry to creating > hallucinations of leaving the body? ... We know that dreaming is important; perhaps the temporal lobe contains mechanisms for producing out of body experiences and these mechanisms have some important use during dreams. (virtual experiences, so to speak). In a teleological sense, these experiences were never meant to be used in virtual mode, only in real mode. Maybe it is important that, as we dream, the experiences must seem real, or they won't have the desired effect. However, when we have a virtual experience while awake (drugs, etc.) it can seem real even though we know we are not dreaming. Thus, because of the limitations of our brains, we can find it difficult, at times, to distinguish between reality and illusion. Which is: 1) probably a useful trait in an evolutionary sense 2) why we need science (and rational, skeptical thinking) Harley Hahn