Medical Science Of Near Death Experience

[Line]

Religious people believe in NDEs but there's debate in Science. They say it's just a hallucination. What if you're hallucinating about something real?

Blind people could help solve this. Habe any blind people with the visual part of their brain permanentlydamged ever had a near death experience?

 

[Curious3141]

http://www.near-death.com/experiences/evidence03.html

Interesting, apart from being unable to discern color (which she had no experience with and hence would not be able to label and identify to a sighted person), she was able to see scenes clearly).

Contrast this with dream experiences of the blind :

http://vision.about.com/od/severevisionloss/f/blinddreams.htm
http://answers.yahoo.com/question/index?qid=1006050303603

Consensus seems to be that congenitally blind people can only cognize auditory and tactile stimuli during their dreams.

Intriguing.

 

[Curious3141]

BTW, maybe this should be moved to S & D - it might get more critical exposure there. Just a suggestion.

 

[Line]

Curious-That doesn't answer the question. She had a permanentally damged optic nerve not visual brain center.

 

[Curious3141]

Curious-That doesn't answer the question. She had a permanentally damged optic nerve not visual brain center.

Actually I believe the site got the medical details muddled. Hyperbaric oxygen treatment of the neonate can cause retinal vascular hyperproliferation, resulting in retinal damage and blindness. This is not the same as optic nerve damage.

In any case, this was a lesion in the "light collecting apparatus" of the visual system. Severe bilateral lesions in these more proximal paths are more likely to give "real" visual deficits than cortical defects (what you refer to as "visual brain center"). Cortical defects can sometimes result in a person who can actually perceive visual stimuli subconsciously but will deny being able to see. The converse can also happen (person cannot see but claims to be able to - Anton's syndrome). With deficits of the light collecting apparatus itself, this sort of disconnect almost never happens.

So if the basic medical details are true and the woman qualified as being legally blind (a visual acuity standard), then to all intents and purposes, she was "truly" blind, in that images weren't getting through to her brain for her whole life. That makes the NDEs fascinating.

 

[Line]

Actually I believe the site got the medical details muddled. Hyperbaric oxygen treatment of the neonate can cause retinal vascular hyperproliferation, resulting in retinal damage and blindness. This is not the same as optic nerve damage.

In any case, this was a lesion in the "light collecting apparatus" of the visual system. Severe bilateral lesions in these more proximal paths are more likely to give "real" visual deficits than cortical defects (what you refer to as "visual brain center"). Cortical defects can sometimes result in a person who can actually perceive visual stimuli subconsciously but will deny being able to see. The converse can also happen (person cannot see but claims to be able to - Anton's syndrome). With deficits of the light collecting apparatus itself, this sort of disconnect almost never happens.

So if the basic medical details are true and the woman qualified as being legally blind (a visual acuity standard), then to all intents and purposes, she was "truly" blind, in that images weren't getting through to her brain for her whole life. That makes the NDEs fascinating.

Yes yes but her optic nerve was damaged, not her visual cortex. Blindness from the eye,optic nerve, and brain are 3 different things.

I need a case where the brain was inactive yet the person was somehow able to see.

 

[Curious3141]

Yes yes but her optic nerve was damaged, not her visual cortex. Blindness from the eye,optic nerve, and brain are 3 different things.

I need a case where the brain was inactive yet the person was somehow able to see.

What are you looking for? "Inactive brain" is about as vague as you can get. I assume your inquiry must be driving towards some point you're making about the supernatural character of an NDE?

Here's my point : blindness due to a cortical lesion cannot be used as evidence to highlight supposed supernatural vision during NDEs. As I've told you, there are rare cases where the visual cortex is damaged and the person cannot see, yet some modalities of visual information still get through. Like this case : http://news.bbc.co.uk/2/hi/uk_news/wales/4090155.stm (I disagree with calling it a "sixth sense", BTW).

There is no reason in principle why a cortical lesion with apparent complete blindness should preclude some sort of visual input - the basic sensory transducers are still intact. Photons are still entering the eye, impinging on the retina and causing biochemical changes in the rods and cones that may induce electrochemical phenomena in the optic nerves, which are potentially transmissible right back to the visual cortex. Note that this sort of mysterious "sight" occurs when fully conscious and not during an NDE.

Hence even if you found an NDE with visual experience in a person with cortical blindness of some sort, I would be inclined to put it down to subconscious visual processing that comes to the fore during the NDE. I would not find that incredible, or even implausible - the person could "actually" receive visual input all along, but denied it up till then. Nothing supernatural about that.

In simple terms, sightedness during NDEs in people with cortical blindness doesn't prove anything.

On the contrary, if the eyes themselves are damaged very badly (as in severe retinal neovascularisation, like in the case I cited), or, better still, there's been complete enucleation of both eyes at birth, THEN any accurate visual experience during an NDE would certainly be supernatural. Because there is no physically plausible way photons from the surrounding could induce electrical activity in such a person's brain during life.

 

[eeka chu]

So did anyone watch Flatliners this week?

NDE's seem obvious to me. I've taken hallucinogens and "tripped my balls off". I'm also a 100% certified agnostic. However, I would actually expect some form of strange activity to occur as the brain suffers such an immense shock as it would approaching a complete failure. I'd also expect that it's a virtual guarantee you're coming out of such an event with at least some degree of permanent damage to your brain whether it's immediately, discretely verifiable or not.

The idea of being able to measure complete brain death using an EEG alone is laughable, muwhuhuhurrrr!

A MEG scanner is about the most accurate form of brain scanner we have available, and even that can't do better than thousands of roughly simultaneous impulse events. So even if I was looking at a guy's brain as he died with a MEG, he could still be neurally active even as my scanner showed him as entirely out of it.

A MEG scanner absolutely destroys a normal EEG in terms of sensitivity and accuracy.

I liked the line in Flatliners from Julia Roberts when the guy suggests that the NDE's could just be hallucinations;

"No, you're just grasping at straws now!"

What? And suggesting that you're getting in touch with a devine intelligence, who just happens to be your god and not someone else's, and that everyone elses' gods aren't right, is more scientific yeah?

Flatliners (The atheist's edition)
"He's flatlining"
"He's dead"
[the end]

Flatliners (The agnostic's edition)
"He's flatlining"
"He's dead"...
"But is he?"
[the end]

 

[Line]

And yes EKA there are people who have taken hallucineginic drugs that describe the same experience as NDEers. They're in an altered state, the go through a tunnel, they enter another world, they have a joyful experience, and come to some contact with "God" or The Universe.

They are finding the same thing without of body experiences. ONe of the results of Ketamine is that takerssometimes go through out of body experiences.

 

[JierenChen]

^^^It is speculated that the brain releases DMT, a powerful hallucinogen, before death.

http://en.wikipedia.org/wiki/Dimethyltryptamine#Speculations

 

[Mk]

How can it be speculated? You mean like "guess to create a rational cause?"

 

[PIT2]

The difference between induced experiences and NDE's is that the induced experiences "consist of fragmented and random memories unlike the panoramic life-review that can occur in NDE. Further, transformational processes with changing life-insight and disappearance of fear of death are rarely reported after induced experiences." - url

But even if the experiences could be fully induced, this says nothing about the reality of the NDE. The conclusion "Aha, we found a chemical, thus 'the chemical = the experience'." does not logicallly follow.

It would only indicate that death is not the only situation where such experiences occur, just like NDE's may indicate that life is not the only situation where such experiences occur.

 

[DMuitW]

I agree with you PIT2, if i may quote myself:

Secondly - and presumably more fascinating for physics – is the mechanism that is responsible for this assumed delocalized mind. When we consider our worldly reality and another implicate reality that may be out there, there should be a mechanism responsible for the connection between these two. When we consider NDE’s, it seems logic to think that this mechanism at a certain moment “lets go” the physical part of which could be connected to the brain.
I note that there are strong indicators that this mechanism doesn’t solely rely on “the physical moment of brain death”, but also may depend on a subjective decision that is in the coextensive reality out there (and therefore is inaccessible to scientific objectivism) . This is backed up by my earlier assumption that standalone spontaneous OBE’s should logically use the same principle of delocalizing the mind, and obviously don’t require brain death. Also, NDE’s occur in comatose patients, who cannot be brain dead as they lived to tell.

The implication of this is that pinning down an exact moment where an NDE or OBE occurs is hard. If indeed there is a physical counterpart that is wired to the brain, it may be possible to detect this, but this may as well be refuted by the apparent “subjective” occurrences of OBE’s that were assumed to fall back on the same principle of a delocalized mind.

 

[quantumcarl]

Religious people believe in NDEs but there's debate in Science. They say it's just a hallucination. What if you're hallucinating about something real?

Blind people could help solve this. Habe any blind people with the visual part of their brain permanentlydamged ever had a near death experience?

If dreaming and hallucination are similar in terms of autonomous-visual stimulation here is a suggestion from some studies pertaining to dreams and damage to the visual cortex.

Mark Solms is a professor of neuropsychology at the University of Cape Town, who originally trained as a neuroscientist but began studying dreams after later training as a psychoanalyst. "You see things in dreams because your visual cortex is excited. You hear things because auditory cortex is excited," he says. "The forebrain connects all the images together in a futile attempt to make a story or an episode out of what's happening. The narrative doesn't mean anything."

Hobson's "activation synthesis theory" remained the accepted explanation for how dreams are generated and Freud's ideas were discounted by mainstream scientists. That is until Solms made the chance discovery that people with lesions on their pons were still having dreams.

"I was taken aback - we know that damage to this structure leads to a loss of Rem sleep and therefore it must lead to a loss of dreaming," recalls Solms. He had disassociated Rem sleep from dreams but it left the question wide open once more: what part of the brain was causing dreams?

The answer came as another surprise. "There were brain structures which, when damaged, led to a cessation of dreaming," explains Solms. One was the part of the brain that processes spatial cognition. But more interesting was the fact that dreaming also stopped with damage to a part of the brain that controlled motivation.

From: http://www.guardian.co.uk/life/feature/story/0,13026,1234739,00.html

It could be that motivation has more to do with the formation and interpretation of mental imagery than the visual cortex or optic nerves.