Talk:Near-death experience

Needs more work

This will need further work. For instance, the "commonly reported experiences" are copied from the source where the are simply a list, and not a sequence of steps. They need to be expanded. --Peter Schmitt 12:44, 12 January 2011 (UTC)

Found some references that might be of interest. The first four aare available as free full text, and the first might be particularly valuable

1. Blackmore SJ (1996) Near-death experiences J R Soc Med 89:73-6. Review. PMID 8683504
2. Greyson B (2003) Near-death experiences in a psychiatric outpatient clinic population Psychiatr Serv 54:1649-51 PMID 14645808
3. Griffith LJ (2009) Near-death experiences and psychotherapy Psychiatry (Edgmont)6:35-42 PMID 20011577
4. Klemenc-Ketis et al. (2010) The effect of carbon dioxide on near-death experiences in out-of-hospital cardiac arrest survivors: a prospective observational study Crit Care 14:R56 PMID 20377847
5. Greyson B (2010) Hypercapnia and hypokalemia in near-death experiences Crit Care 14:420 PMID 20519028
6. Beauregard M et al. (2009) Brain activity in near-death experiencers during a meditative state Resuscitation 80:1006-10 PMID 19573975
7. Belanti J et al. (2008)Phenomenology of near-death experiences: a cross-cultural perspective Transcult Psychiatry 45:121-33 PMID 18344255
8. Lai CF et al. (2008)Impact of near-death experiences on dialysis patients: a multicenter collaborative study Am J Kidney Dis 2007 50:124-32, 132.e1-2 PMID 17591532
9. Parnia S et al. (2007) Near death experiences, cognitive function and psychological outcomes of surviving cardiac arrest Resuscitation 74:215-21 PMID 17416449
10. Greyson B (2007) Consistency of near-death experience accounts over two decades: are reports embellished over time? Resuscitation 73:407-11 PMID 17289247
11. French CC (2005) Near-death experiences in cardiac arrest survivors Prog Brain Res150:351-67. Review PMID 16186035

Gareth Leng 15:05, 12 January 2011 (UTC)

Yes, the article needs more work but when I searched for this topic it came up as needing a brief overview. It was not asking for a full length fully researched article. Also, being a wiki it should be expected that others would contribute to writing an article. As my mother used to say "many hands make light work" and she was right. It's also a lot of fun when we can work together collaboratively to get the job done.Mary Ash 16:18, 12 January 2011 (UTC)

And here's some more links you can check out:

http://www.nderf.org/

http://www.npr.org/templates/story/story.php?storyId=104397005

http://www.time.com/time/magazine/article/0,9171,1657919,00.html

http://articles.cnn.com/2009-10-16/health/cheating.near.death_1_geraghty-cardiac-arrest-school-bus?_s=PM:HEALTH

http://www.livescience.com/health/080912-near-death.html

http://www.iands.org/pubs/jnds/

• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1295660/

• http://folk.uio.no/benjamil/neardeath/neardeath5d.pdf

• http://books.google.com/books?hl=en&lr=&id=2F8W3MAXCVIC&oi=fnd&pg=PA4&dq=%22near+death+experiences%22&ots=qBCQiCh_sR&sig=RZcdCoCB7vY4cZ-BXMkvhWv94DI#v=onepage&q&f=false

• http://www.ethicsforschools.org/nde/death.htm

• http://ajp.psychiatryonline.org/cgi/content/abstract/137/10/1193

• http://www.resuscitationjournal.com/article/S0300-9572%2800%2900328-2/abstract

• http://www.ncbi.nlm.nih.gov/pubmed/7403383

• http://www.ncbi.nlm.nih.gov/pubmed?term=%22near%20death%20experiences%22&itool=QuerySuggestion

• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2887177/?tool=pubmed

• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2790400/?tool=pubmed

• http://www.ncbi.nlm.nih.gov/pubmed/17289247

• http://www.ncbi.nlm.nih.gov/pubmed/16534440

Mary Ash 18:01, 12 January 2011 (UTC)

A list of links, without analysis, doesn't really help; each would have to be read. I'm afraid this article assumes the existence of NDEs and looks for support. NDEs are by no means an accepted phenomenon in medicine. Howard C. Berkowitz 18:01, 5 February 2011 (UTC)

Highly questionable assertion

"NDEs occur once a person's heart function stops causing the blood supply to cut off to the brain. This usually takes between 11 to 20 seconds once the heart function ends. An electroencephalogram (EEG) reading taken during this time will show a flat brain waves."

Sorry, but this is just wrong. In a patient with normal body temperature, it takes 4-5 minutes (240-300 seconds) of no effective cardiac action for there to be significant brain damage, and, even then, it's not an isoelectric EEG. Other factors can extend the time. Until I get my new pacemaker on Tuesday, I'm sure, from previous experience, I've had several cardiac pauses in the 15 second range. Howard C. Berkowitz 18:01, 5 February 2011 (UTC)

This is an exact quote from the article: So what's so baffling about NDEs? We know that when a person's heart stops, the decline in brain function caused by a cut in blood supply is steep. Simultaneous recording of heart rate and brain output shows that within 11 to 20 secs. of the heart failing, the brain waves go flat. A flat electroencephalogram (EEG) recording doesn't suggest mere impairment. It points to the brain having shut down. Longtime NDE researcher Pim van Lommel, a retired Dutch cardiologist, has likened the brain in this state to a "computer with its power source unplugged and its circuits detached. It couldn't hallucinate. It couldn't do anything at all." Perhaps I wrote this section poorly, and if you can rewrite it to reflect the exact quote above go for it. As this statement is made by a retired Dutch cardiologist, who is a medical doctor, the claim has validity. I'd suggest having one of our medical personnel review this statement and add updated information, if that's available. Mary Ash 18:43, 5 February 2011 (UTC)

Read more: http://www.time.com/time/magazine/article/0,9171,1657919-2,00.html#ixzz1D6xJFWZj

I don't consider Time Magazine an authoritative source on the subject and I'm not going to go and read it. It's a bad source for an encyclopedic article. My textbook on cardiopulmonary bypass is a lot more authoritative. Given that there are journal articles, I see no point at all in going to news magazines.

Time doesn't really tell if the cardiologist is current or not, and I'm not going to argue with Time when, for example, protocols for determination of death say something quite different. Flatline EEG is generally consistent with death, not near death, although such things as brain perfusion are preferable to EEG.

As written, this article comes across as assuming that NDEs are common and scientifically confirmed. It's more correct to say that a minority of people who have been resuscitated, report a generally consistent experience. Howard C. Berkowitz 18:57, 5 February 2011 (UTC)

The article clearly states 23 million people have experienced NDEs. That is a clear cut number. As to the rest, and what I posted in the forum, have one of our medical doctors review the article for accuracy.Mary Ash 05:55, 6 February 2011 (UTC)

Time Magazine is not a reasonable source. I have gone through the actual medical articles and none make a sweeping statement about how many people have experienced the phenomenon. Howard C. Berkowitz 06:10, 6 February 2011 (UTC)

{unindent} Howard a Time magazine reporter was interviewing a retired medical doctor about this. An MD is an MD and his testimony is expert testimony. Two other medical doctors are referenced in the article along with a psychologist who taught at the university level. All would be considered expert witnesses and investigators. You can go to PubMed and you will find all kinds of information concerning this subject. In fact, here's a link to get you started: http://www.ncbi.nlm.nih.gov/pubmed?term=near-death%20experiences. Have fun!Mary Ash 06:57, 6 February 2011 (UTC)

"An MD is an MD". Blatantly untrue. If it were true, there would be no specialties. Indeed, neurology would be more relevant.

You cannot make the assertion they would be experts. In law -- and I have been an expert witness -- the court makes the determination. In science, the state of expertise comes from professional practice, not the opinions of a general circulation magazine.

I have gone to PubMed many times. The very fact that again, you throw out a generic search in the claim that it supports your argument shows a lack of understanding of the process. Journal impact factor cannot be considered based on a search. Howard C. Berkowitz 07:04, 6 February 2011 (UTC)

Howard part of research is going through the documents. I posted a link for near-death experiences which you can explore at your leisure. There are many to choose from and I did search PubMed for this article by typing in Near-Death Experiences.Mary Ash 07:27, 6 February 2011 (UTC)

Mary, it is not part of CZ research to require others to go through a general bibliography. Spot-checking a few of the specific reference, I'm concerned that they were cherry-picked.

Further, you aren't responding to the point that general science reporting is questionable for encyclopedic articles, at least as authoritative statements as Gareth explains below. Howard C. Berkowitz 12:44, 6 February 2011 (UTC)

While I don't have an opinion on how accurate the source is, I must say the article was very enjoyable to read. I am surprised Mr. Berkowitz experienced cardiac pauses for 15 seconds. Would you be able to describe what it felt like? I think I also occasionally experience heart attacks, although when I described the symptoms to my family they said it wasn't the real thing. (Chunbum Park 23:29, 27 February 2011 (UTC))

The pauses happen only in my sleep, so I can't really tell you. Nevertheless, I have personally been present at monitored incidents in a neurological intensive care unit, and the brain simply does not stop after short heart pauses. I also gave a reference from a standard textbook of cardiopulmonary bypass.

I suppose I can go get some cardiology and neurology texts as well, but it doesn't seem to help explain things here. Howard C. Berkowitz 23:58, 27 February 2011 (UTC)

To summarise on this point - Mary's "highly questionable assertion" is in fact correct. In the absence of perfusion the brain has sufficient energy stores to survive for about 5 minutes, after which damage is irreversible. But the EEG flattens quickly, indicating rapid loss of brain electrical activity. There may be occasional spikes, but the statement as made is correct; the rhythmic activities that characterise a normal EEG go, and that's the normal understanding of a flat EEG. The statement is also correct in stateing the NDEs in cardiac arrest seem to occur in this window of falling EEG activity before irreversible brain damage occurs. Gareth Leng 16:15, 28 February 2011 (UTC)

{unindent}Thanks Chunbum Park! I tried to make the article interesting while being educational. Once in awhile my heart skips a beat or two but this is fairly normal. Here's a link: http://heartsmartmd.blogspot.com/2010/02/skipping-heart.html about PVCs. If you have other symptoms such as dizziness, etc. then of course a doctor should be consulted. Mary Ash 06:19, 1 March 2011 (UTC)

Thanks Gareth. I did remove the original statement concerning brain wave activity and the dying process as it seemed controversial. I have since read a more detailed explanation by a different medical doctor that backed up the earlier statement. I did not include this in the article. As best as I can determine, and I am not a medical doctor nor esteemed biologist like you; but it seems the NDE is part of the dying brain and not a dead one. If this is the case, the information would indeed be accurate as nothing shuts down at once. There are variances in body functions during the dying process. Or to put a different spin on it, when I was a girl I saw a large cotton mouth rattlesnake die. The head was chopped off from the body yet the mouth of the rattlesnake continued to snap for awhile after the snake was killed. I presume this was caused by the final dying moments of the snake's neurological system. Death is not instant but a process of shutting down. Is this a good way to look at the process? Mary Ash 06:19, 1 March 2011 (UTC)

Keep cool

On some key points - "near death experiences" (meaning a consistently reported set of experiences generally in situations of oxytgen deprivation) are indeed common. How common is very questionable - Howard is quite right in that what an MD says in an interview is evidence of his opinion but not evidence of any facts; but it is attributed in the article to an individual. The experiences are fairly well documented and seem to have a reasonably well understood physiological basis. I've no idea what the heat is about this article. In my experience, what science journalists report is often wrong in almost every significant detail, but usually there's some snippet of a foundation. Of course, what journalists say is important to know even when it's wrong, because their version may be what becomes the public perception. So we have two things that need to be known: a) what journalists say (and what the common or public understanding is) and b) the facts.

Anyway; I think this is an interesting topic and you've made a great start to it Mary. Gareth Leng 11:39, 6 February 2011 (UTC)

Sure. While I have seen no trustworthy figures about their total incidence in the total population, there certainly are legitimate articles that state that they are reported in a substantial minority of patients who have been resuscitated, and had adequate neurological function to describe their experience. Scanning the cited abstracts, but not doing a formal combination of samples, it would appear to be in the 10-20% range.

My specific concern was the statement that brain activity, as evidenced by an isoelectric EEG, ceases within seconds after cessation of cardiac activity. Actually, I'd be interested in knowing the provenance of that claim, since patients in critical care rarely have EEG monitoring. "The value of routine EEG monitoring during cardiac surgery is controversial", from Gravlee, Davis & Utley, Cardiopulmonary Bypass: Principles and Practice. Nevertheless, the body of experience in resuscitation is that brain activity continues for short minutes before irreversible damage begins, and, even then, there would be a declining, not sudden, stop of energy detectable on EEG.

My more general concern is that general journalistic reports are not always, as in this case, appropriate sources. They are clearly necessary in such things as current politics and war, when the journalist is a direct observer or has unique access to policymakers (especially when non-anonymous). For science and engineering, however, there is almost always a more authoritative source. Howard C. Berkowitz 12:44, 6 February 2011 (UTC)

Near-death EEG

In rats, after decapitation, peaks after about one minute, and then flattens. --Daniel Mietchen 15:24, 6 February 2011 (UTC)

Thanks Daniel! Mice tend to die quick although I've never had the reason to kill any. NIH states brain cells start dying 5 minutes after brain hypoxia occurs. See: [1] I can't remember the exact number I was taught as an EMT student, but it was something like you had 7 minutes before brain damage was likely. It's been too many years ago since I aced the class. On a side note, my kids still wonder about their mother who loved to dissect critters in biology class. There were only two things I did not like dissecting: the Sea Cucumber as it squirted formaldehyde in my face and the cow's eyeball. While the eyeball was very interesting, it just creeped me out every time I had to work on it. I also received "A" grades for my drawings. There are days when I think about taking some more biology classes but I've taken all that are available locally. In fact, long ago my biology teacher wanted me to attend medical school, and thanks to her I received a very nice award from our medical society, but the money was not there. Instead I opted for a degree in English with almost enough units for a minor in biology. Never got the time to finish the course work as I was busy working and going to school. Thanks for your kind words. I look forward to the article blossoming and I will try to work on it later. Right now I have a doll I need to finish painting, a garden to plant and I am busy sewing a couple spring dresses for my daughters. In other words keeping busy.Mary Ash 16:36, 6 February 2011 (UTC)

Have we, then, established that the Time quote about brain activity ceasing in seconds is implausible? Howard C. Berkowitz 17:30, 6 February 2011 (UTC)

The Time quote seems to have disappeared. I had been consulting with clinicians in this area, and was asked to get the exact text so that it could be reviewed on a critical care medicine mailing list. Could someone help me find the exact language of the claim that the EEG went isoelectric within a short number of seconds of the cessation of effective heartbeat? I will send it to specialists for review.

There is certainly nothing wrong with getting multiple expert opinions. Howard C. Berkowitz 01:02, 2 March 2011 (UTC)

Sources

Yes, there are better sources available, at a good guess, but I can see me explaining to my husband why I spent almost $40 for a Kindle book (not a bound book but an electronic book) or why I purchased article rights for xxxx amount of dollars for a volunteer project. I will continue to look for free sources but they are scarce. BTW Greyson is an MD and teaches in the department of psychiatry. Also, I could be wrong but I think he's a neurologist. Mary Ash 00:35, 7 February 2011 (UTC)

Whether this is being testy or not, on my shelf are the aforementioned cardiopulmonary bypass textbook, as well as standard textbooks in cardiology and neurology. I have studied them and associated material, and was a developer of advanced cardiac life support simulators at George Washington University Medical School's Office of Computer Assisted Education, around 1977 or so -- this is not new material One could look at any of a number of protocols for determination of death and find that short heart pauses are not even considered.

In other words, and Hayford might be able to phrase this more diplomatically, there is an assumption, at CZ, that when one goes to a source, one has the background to understand it, work with its contents, and contextualize it, rather than simply paraphrasing it. If you have to get basic books or articles on a subject, perhaps you might not be the best person to be doing encyclopedic writing on it. Even the EEG, these days, is less preferred than other brain imaging techniques. Howard C. Berkowitz 00:04, 28 February 2011 (UTC)

Howard, this is not only inappropriate, it is inaccurate. Anyone can author here. D. Matt Innis 02:18, 28 February 2011 (UTC)

Howard, your comment on EEG is technically misguided; brain imaging techniques are not an alternative to EEG; they measure totally different things. I think this article is outside your sphere of editorial expertise; it is within mine and I'll be happy to offer Mary guidance if she has the patience to wait for me to have time.Gareth Leng 09:38, 28 February 2011 (UTC)

Gareth, I am not speaking as an Editor. I will, however, argue, and source, that brain perfusion scans, and other techniques, are preferred to EEG in most of the clinical protocols I know, for determination of death and readiness for transplantation. In another article, Daniel and I had some discussion about using "imaging" a bit loosely; some systems do consider EEG within it. Note that evoked potential monitoring is used increasingly to monitor anesthesia level, and, especially, consciousness during anesthesia.

Mary made the statement that the EEG goes isoelectric within seconds of effective heart activity. I say, and will source, that is nonsense. Do you disagree? Howard C. Berkowitz 09:57, 28 February 2011 (UTC)

I don't have the time to review the content now, and the statement you make above is incomprehensible in isolation. It is to be expected that authors sometimes make mistakes, that's why we have editors and that's why their gentle guidance is needed. Don't blame authors for not being experts.Gareth Leng 10:10, 28 February 2011 (UTC)

OK I have now checked this specific statement. First, Mary's quote is accurate from Time magazine; it comes from van Lommel, the lead author of the Lancet paper 'Near-death experience in survivors of cardiac arrest: a prospective study in the Netherlands' (2001) 358:2039-2045; that Lancet paper contains essentially the same statement, "Also, in cardiac arrest the EEG usually becomes flat in most cases within about 10 s from onset of syncope". Similar statements appear commonly in the neurological literatute, and that statement is certainly consistent with animal studies; in cats for example (Fischer & Hossman, Intensive Care Med (1995) 21:132-141) "After onset of ischemia EEG flattened within 20 s." It's also exactly what I'd expect in lab animals, and consistent with studies in humans of transient ischemia. On criteria for brain death, the American Academy of Neurology guidelines are here. Evoked potential measurements are EEG measurements, and I certainly don't know a better way of measuring brain electrical activity than by measuring brain electrical activity.Gareth Leng 14:26, 28 February 2011 (UTC)

The AAN guidelines do not address the specific point of the short-term time relationships between cardiac activity and an isoelectric EEG. I do have access to a group of intensivists, to whom I had wanted to submit this point, given that the cited references are at least 10 years old. Since then, there's been a huge amount of work in signal processing both of the classic EEG, and, where there is greater interest, evoked potentials, which are similar but have somewhat different design.

At the very least, I would hope that this can be discussed not just with battling citations, but what they actually mean. Howard C. Berkowitz 18:55, 2 March 2011 (UTC)

Indeed; the EEG is a high pass filtered signal, not a dc signal; an isoelectric EEG is a "flat" EEG with little AC component; AC components arise from synchronous neural activity, and the characteristic waves arise from synchronous rhythms. A flat EEG and indeed the complete cessation of electrical activity is not necessarily indicative of brain death. The acute "peaking" of the EEG after ischemia is itself a 'flat' trace - in that it has no high frequency components - this is essentially the profile that you'd expect from sustained indiscriminate depolarisation leading to depolarisation block, and this is what you'd expect from absence of perfusion, as it will arise as a result of a rapid build up of extracellular potassium (released from active or damaged neurones), which would normally be cleared from extracellular space into the blood via astrocytes. Neurones fall quiet when either hyperpolarised or strongly depolarised (via depolarisation block), and a flat EEG is indicative of the absence of synchronous episodes of activity and rhythmic activity; there may still be some neuronal electrical activity present, but this seems unlikely and very unlikely enough to subserve meaningful information processing. Probably all meaningful information processing is over within maybe 10-20 s of acute ischemia. That's plenty of time for the kind of "perception" we get in dreams. There's no technical value in discussing the EEG in this article that I see except in support of what I think would be generally accepted, that cognitive brain activity ceases swiftly after acute ischemia though irreversible brain damage only arises after about 5 min of anoxia. The meaning of these data is thus that meaningful cognitive processing ceases within a very short time of ischemia. Whether that's 5s or 10 s or 20 s is by the way I think. But maybe I've missed something? My account here and below is largely a reconstruction from standard neurophysiology, and I'm open to correction; long time since I actually recorded EEGs myself. Gareth Leng 19:24, 2 March 2011 (UTC)

Added more info

I've spent about two weeks reading and researching this topic. I then spent another 16 hours writing about this subject. I have posted the new information for all to view. I have also included the original article at the bottom of the page as to not remove any potential edits from other contributors. Editors please note what I did. Thanks!Mary Ash 06:02, 27 February 2011 (UTC)

Mary, that is simply not the way to do things at CZ (leave the earlier material at the bottom of the article). I haven't read the article, and I'm not going to, but I will say that all articles have to follow our general CZ formats. Having two sets of info on the same page is not how we do things. I suppose I could just delete all the stuff at the bottom, but I'll leave it up to you to correct things. If Howard gets testy about this, don't say that you haven't been warned. Your intentions here may be pure, but your execution is lacking. Please fix this. Thanks! Hayford Peirce 23:49, 27 February 2011 (UTC)

Yes, Mary, I agree with Hayford. Please merge the material or delete it with explanations on the talk page if you feel it will be a controversial edit. D. Matt Innis 02:21, 28 February 2011 (UTC)

Deleted. I didn't want to ruffle any feathers. Also, I would like the new definition returned. The new one clearly stated what this article is about and the old one replaced by another contributor does not.Mary Ash 03:00, 28 February 2011 (UTC)

Your definition, Mary, does not define NDE (as it should) and cannot be returned. It describes a purpose. And if your definition, "Near-Death Experiences as reported by patients who nearly died but returned to life", corresponds to your intentions then this shows a fundamental misunderstanding: A main space article on NDE has to sum up what is known about this phenonemon. It certainly is not the place to collect reports.

The place for such a list can be a Catalog subpage, but even there a more systematic presentation (with comments) would be better.

Did you notice that there are no references shown?

--Peter Schmitt 09:40, 28 February 2011 (UTC)

Simply stating that one wants a definition returned, with no sourced explanation, suggests a position of ownership of the article. Howard C. Berkowitz 09:57, 28 February 2011 (UTC)

Making a polite request/suggestion on the Talk page is not asserting ownership. I'll be happy to review Mary's suggestions for changes in the article and provide editorial guidance in time, but I don't have the time this week at least.Gareth Leng 10:05, 28 February 2011 (UTC)

May I also suggest that it's good practice to check on the academic literature before making an assumption of fact on an issue that is disputed? NDEs are not confined to cases of cardiac arrest. Quoting from Blackmore's review article in J Roy Soc Med (link given above), "NDEs often happen to people who think they are dying when in fact there is no serious clinical emergency. This adds to the general conclusion that you don't have to be physically near death to have an NDE" Mary's definition is not perfect, but it's better than both the one it replaced and the one it's replaced by.Gareth Leng 15:59, 28 February 2011 (UTC)

Preliminary suggestions

I've read through the article now and made just a few minor changes, mainly to how references are cited (see the style for how to repeat citations - you don't need to repeat the reference citation in full).

You've gathered together a lot of content that you'd like to include, and no doubt want to add more. This is content that you've found interesting - and that's always a good way to start, because what you find interesting/intriguing is the best guide you have as to what others will. I think you will want to think about how to structure the article better - you don't want lots of short sections, rather you want longer coherent sections that serve a distinct purpose. For example, what's the point of covering reports from different regions? Well there's an important purpose here, it's to show that how we interpret an NDE depends on expectation, and this varies with cultural background. So given that that's the key message, those elements form part of a single section given to that purpose, and you can lose the separate headings.

NDE's are interesting to neurologists, they're common, distinctive and relatively stereotyped, and these speak to a common underlying physiological explanation. Speaking as a neurophysiologist, there are certain things I'd expect to follow from acute ischemia. The brain will not be affected uniformly, far from it. The first messages to the brain after induction of ischemia will be carried in neurones that regulate the cardiovascular system. These will be activated by chemosensors responding to low oxygen, high CO2 levels, to a fall in blood pressure and to signals from blood volume (low pressure) receptors. These will affect key areas of the caudal brainstem and hypothalamus. There will be a swift and strong activation of the "stress axis" in the hypothalamus. The hypothalamus is the key origin of "emotionality", and many of the same neuronal pathways engaged in the stress axis and cardiovascular reaction also affect a wide range of emotional responses/behaviours - surprisingly so. For example, the vasopressin system, activated by a fall in blood pressure, also powerfully influences pathways that are a key part of "bonding" behaviour, including what we might call love.

After activation of these early systems come the more direct effects of low oxytgen on all neurones, but these will not be affected simultaneously. Different neuronal populations have very different metabolic requiements, so some will fail faster than others. Failure doesn't mean "dying", rather it means that some populations will be strongly activated and then fall silent, while others just fall silent - and this depends in part on how they are interconnected with other groups of affected neurones, but there are lots of factors. Let's consider some examples: in the retina, the greatest density of photoreceptors is in the centre of the visual field, so as these receptors or interneurones in the retina fail, it seems likely that some disorganised activity in the centre of the visual field will be present when activity in the periphery is gone - and this may explain the perception of a "tunnel" or "bright light". Signals from the periphery and from the retina are "interpreted" by higher centres - that's their role, to make sense of whatever signals they receive, and the sense that they make of those signals is conditioned by expectation and experience. It seems likely that cortical neurones - the highest of the higher centres - are relatively slow to be directly affected by ischemia, so they will be trying to somehow interpret the disordered signals, some of which will randomly evoke memories. Now the perception of time will be distorted - when we dream, we may experience the dream as very long even when it takes only a few seconds, and the whole NDE, even if it is experienced as prolonged, may in fact be all compressed within just a few seconds.

So what we need to get across is that the NDE is what someone experiences, meaning that this is how their brain, in conditions of extreme stress or anoxia, interprets the disordered signals that it is receiving. The experiences are consistent between individuals because broadly in the most common conditions the sequence of brain changes is similar. The experiences have strong emotional significance in part because they are very strongly accompanied by the neurohormonal signals from the hypothalamus that attach emotional significance to events - so these are interpreted as "spiritually meaningful"

What is important is to be consistently clear that while the NDE is "real" to the person that experiences it, it is, sadly, simply the interesting consequence of a brainstem desperately signalling an emergency in a very disorganised fashion to higher centres that are organised to make try to make sense of these signals. What sense is made of these signals is influenced by expectation, so they will be interpreted differently by children and adults, and differently by people in different cultures - and they will be different depending on the precise trigger for the NDE.

Once we have the structure and narrative developed we can go back to refine the referencing. The sources are mostly fine, and certainly fine for now, but we'll want to move to the strongest references possible, and replace some book references with references to the research literature - which fortunately is quite substantial and solid. Some of those sources are listed above, and this is something I'll help closely with in due course.

We don't need to use "close referencing" - you've given page numbers of the books and that's great practice in an early draft, but progressively we'll want to thin out the referencing, while bringing in more academic sources.

I've written at length here, just to give you some ideas and thoughts about how to progress: I hope they're helpful. I won't write more on the article at this stage to let you develop it yourself first, but at a later stage I will probably step in to help refine. Gareth Leng 17:17, 1 March 2011 (UTC)