Near-death experiences and consciousness

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The most remarkable thing, Van Lommel says, is that his patients have such consciousness-expanding experiences while their brains register no activity.[...] How can people experience consciousness while they are unconscious during a cardiac arrest (a clinical death)?

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clinically dead ≠ brain dead.clinical death is when the cardio-pulmonary system stops. usually a person can be revived with cpr, or with electrical stimulation.brain death is when all electrical activity in the brain stops. to the best of my knowledge, brain death is by definition not reversible. instances where an eeg reports no activity but the patient is revived are not considered brain death, iirc. i think the declaration needs to be confirmed a day later for it to stand.anyways, this is from the actual article:

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With a purely physiological explanation such as cerebral anoxia for the experience, most patients who have been clinically dead should report one.

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(see above for reference)

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this in the interpretation part of the abstract. it's just not good science. that's like saying that since speeding is a leading cause highway fatalites, most people who speed should die on the highway. causation is not commutable like that. although a factor may contribute to one effect, it is not gauranteed to contribute to the same effect in all situations.similarly, i could make the same claim regarding religion: if nde's were geniune spiritual experiences, why don't ALL clinically-dead-and-revived patients report it? the study shows 18%, and 12% that reported the standard experience.12%.doesn't that make it an usual occurance? so does everyone's conciousness live outside their brain, or just 12%?

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Nevertheless, some scientists continue to assert that these experiences must happen at a time when there is still some brain function going on. Van Lommel is crystal clear in his response: “When the heart stops beating, blood flow stops within a second. Then, 6.5 seconds later, EEG activity starts to change due to the shortage of oxygen. After 15 seconds there is a straight, flat line and the electrical activity in the cerebral cortex has disappeared completely. We cannot measure the brain stem, but testing on animals has demonstrated that activity has ceased there as well. Moreover, you can prove that the brain stem is no longer functioning because it regulates our basic reflexes, such as the pupil response and swallowing reflex, which no longer respond. So you can easily stick a tube down someone’s throat. The respiratory centre also shuts down. If the individual is not reanimated within five to 10 minutes, their brain cells are irreversibly damaged.”

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how do we know the experiences are happening, or the memories being added while the brain is inactive? the brain works in very strange ways -- have you ever had a dream that took hours while you dozed off for a few minutes? i remember dreams that centered around a particular sound. where did the minutes of lead-up to a momentary experience come from?now, i've seen two bits of evidence, and one bit of non-evidence that kind of hamper this particular interpretation.

1. airforce pilots report them all the time: during g-force centrifuge training. draining the blood from the brain produces all the stereotypical symptoms including tunnel vision, bright lights, out of body experiences, and the occasional flashback.
2. ketamine has been known to produce similar results, which is why they stopped using it.
3. i heard of a study (if someone can find this, please do) where an exceptional number of nde were beng reported in a particular hospital. since many reported looking down on their dying bodies in the er, they placed various signs on top of equipment, hanging lights, etc, coded with colors and messages and such. to my knowledge, no one reported them after an nde, let alone got the right answer. that suggests that nde's are something internal, not external.

there's another similar phenominon, too: sleep paralysis. it's also been known to produce out of body experiences, and sensations of weightlessness. lots of people report these experiences as alien abductions or demonic visitation, because it's usually accompanied by visions of distorted figures and extreme terror. but those who understand it can control it to a degree, and make it go away.the brain simply does strange things. who's to say that memories involving the passage of time and events are really indicative of the passage of time or events?This message has been edited by arachnophilia, 11-29-2005 11:28 AM

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it mentions the acronym "EEG" a few times. once in anecdotal sense (?!?) and once in a presumed sense (ie: "EEG usually becomes flat 10 minutes after cardiac arrest").but no, they don't seem to actually be studying brain activity. well, there's another anecdote, actually involving a flat eeg, with a reference:

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22 Sabom MB. Light and death: one doctors fascinating account of near-death experiences. Michigan: Zondervan Publishing House, 1998: 37-52.

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This message has been edited by arachnophilia, 11-29-2005 11:38 AM

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Brain death - Wikipedia well, not really. the brain doesn't need to be active the whole time, just the btis before and after. we like to fill in stuff, and compensate for holes in our memory. the brain also has a high degree of activity while it's running out of oxygen -- and THOSE effects seem to explain nde's. the simply occur BEFORE brain activity ceases (or appears to cease).

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i wasn;t trying to be misleading. i was trying to be funny. well, actually, i assuming that the section of nde patients was a representation of the species as a whole. admittedly, it's faulty logic -- i was just extending it along the lines the "study" failed to.they were using the absence of commonality to all cardiac arrest cases as evidence that it was not physiological -- when in reality there are many other factors, such as: etc. the fact that it happens RARELY doesn't mean that it's not a natrual phenominon.

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randman, i showed you several pictures of skulls in the other thread. if you wanted, you could track down a museum and see one for yourself. presuming you were allowed to, you could pick it up and hold it in your hands. you can own one, too -- i actually have a ancient whale vertebrae and rib myself.can you show me a picture of your nde? can i go to a museum and see one? can i hold it in my hands? can i own one?

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and apparently meaningless. uh, i'm not really sure. i could look stuff up -- mostly it's from psych classes learnign about memory and perception. by falsify, you mean "what would support nde's being real spiritual experiences without naturalistic explanations?" i dunno. how can you falsify that gravity isn't caused by invisible pink ninjas with magnets?

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the brain also has a high degree of activity while it's running out of oxygen -- and THOSE effects seem to explain nde's.

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peer review and publication of a study in a scientific journal doesn't mean all of the author's opinions and beliefs are facts. or, if you had read the study you were talking about:

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And yet, neurophysiological processes must play some part in NDE. Similar experiences can be induced through electrical stimulation of the temporal lobe (and hence of the hippocampus) during neurosurgery for epilepsy,²³ with high carbon dioxide levels (hypercarbia),²⁴ and in decreased cerebral perfusion resulting in local cerebral hypoxia as in rapid acceleration during training of fighter pilots,²⁵ or as in hyperventilation followed by valsalva manoeuvre.⁴ Ketamine-induced experiences resulting from blockage of the NMDA receptor,²⁶ and the role of endorphin, serotonin, and enkephalin have also been mentioned,²⁷ as have near-death-like experiences after the use of LSD,²⁸ psilocarpine, and mescaline.²¹

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4 Lempert T, Bauer M, Schmidt D. Syncope and near-death experience. Lancet 1994; 344: 829-30. [PubMed]
21 Schrter-Kunhardt M. Nah--Todeserfahrungen aus psychiatrisch-neurologischer Sicht. In: Knoblaub H, Soeffner HG, eds. Todesnhe: interdisziplinre Zugnge zu einem auergewhnlichen Phnomen. Konstanz: Universittsverlag Konstanz, 1999: 65-99.
23 Penfield W. The excitable cortex in conscious man. Liverpool: Liverpool University Press, 1958.
24 Meduna LT. Carbon dioxide therapy: a neuropsychological treatment of nervous disorders. Springfield: Charles C Thomas, 1950.
25 Whinnery JE, Whinnery AM. Acceleration-induced loss of consciousness. Arch Neurol 1990; 47: 764-76. [PubMed]
26 Jansen K. Neuroscience, ketamine and the near-death experience: the role of glutamate and the NMDA-receptor. In: Bailey LW, Yates J, eds. The near-death experience: a reader. New York and London: Routledge, 1996: 265-82
27 Greyson B. Biological aspects of near-death experiences. Perspect Biol Med 1998; 42: 14-32. [PubMed]
28 Grof S, Halifax J. The human encounter with death. New York: Dutton, 1977.

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anyways, not to be accused of quotemining, the article is say that those explanations do not fully explain the phenominon. the above is immediately followed by:

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These induced experiences can consist of unconsciousness, out-of-body experiences, and perception of light or flashes of recollection from the past. These recollections, however, consist of fragmented and random memories unlike the panoramic life-review that can occur in NDE.

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no reference given, but i'll assume for the benefit of the doubt it's talked about in one of the above references.

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Further, transformational processes with changing life-insight and disappearance of fear of death are rarely reported after induced experiences.

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and that's simply a result of the interpretation of the event by the cardiac arrect victim. if you black out while in a g-force simulator, you're not going to think you died and went to heaven, and if you have a hallucination while on lsd, you're more likely to rationalize it as such. but if you're on the operating table, and you die, you're less likely to think it was a product of your own biology. the fact that it means something to someone doesn't make it real, or an external phenominon.the article is arguing, basically, that biology alone is not enough. which is a "duh" statement. if we're counting after effects like the ones above, we're obvious including psychology. it's a call for explanation, not an explanation.what i am saying is that i consider the physiological and biological causes, when added to the psychological ones, to be enough, because the lack of an external meaning is contextual, and the fragmentation of memories is not a large enough difference. it's the same process, with similar results -- no suprises here.but i do agree with one point in the article: it should be studied more.

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you forgot a word: "presumed." it should read:"NDEs occur when the BRAIN IS PRESUMED TO BE NOT FUNCTIONING."that's what the bit at the beginning of the thread about eeg's was all about. they're assuming flat-eeg's, not measuring flat-eeg's. they're collecting data about cardiac arrest patients, and that data does not include eeg data.it includes one anecdotal reference to an instance of such a thing happening. but the article itself does not establish that nde's are percieved to be happening when the brain is not function at all. in fact, a flat eeg doesn't establish the non-functionality of the brain; it just esatblishes that the activity is belong the recordable threshold.and even if the perception is that these events happen whole there is no brain activity period, that doesn't mean they neccessarily did -- false memories, hallucinations, blackouts, and dreams tend not to occur in real time, so it's really impossible to sync up the brain's subconcious perception of time to a real clock.so it's on pretty shaky ground to start with.

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i'm arguing that they didn't measure it, just collected statistics about nde's during cardiac failure. i'm also arguing that interpretation is logically invalid, and the reading of that interpretation equally bad.but i'll tell you what; i'm gonna sit this one out until someone finds the sabom reference, and posts. i wanna see what it actually says first, before i say anything about it.

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well, not neccessarily. there are whole accounts from my childhood that i "remember" only because a picture was taken. the actual memory of the event has long since vanished, but i can remember parts that have been reconstructed from the image. i don't really think it's a problem -- nde's don't tend to take very long. and a lot of the information is provided by the effects of a brain dying of oxygen deprivation (see all the references before) i wanna see what that sabom paper says. i'm inclined to not believe that (as test i heard about yeilded nothing). no no, what i was saying above is that a flat eeg may not actually mean ZERO brain activity. it just means it's not strong enough to get a reading.

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quite.

oh, i see. this doesn't look good at all.from the amazon.com review:

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And he scrutinizes near-death experiences in the light of what the Bible has to say about death and dying, the realities of light and darkness, and the Gospel of Jesus Christ.

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doesn't sound like a peer reviewed science paper one bit.so we have a third-hand surgeon's anecdote that went throught a decidedly fundamentalist christian and pseudoscience filter, misreported in a peer reviewed paper?i must say, i'm losing faith in this whole "peer reviewed" thing.

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i think that statement says more about van pommel than the data. and sadly, i think that's a mark against the lancet. seriously, third-hand anecdotes in a science article?

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What completely goes beyond you is that such overstatements "for effect" are no sober, reasoned, objective analysis and have no place in science education and presentation.

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yes, takes you right to the front cover. you need a google account to read it, which i have; so no problem there. i'm not gonna read much of it, but i did skim the relevent passages in your other post.

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not in a scientific study, it's not. seriously, look at the source he cited. is it another scientific study? does it look like valid science?

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