Freethought & Rationalism Archive

ps418 · 11-29-2002, 12:48 PM

One of the most interesting aspects of the NDE is the 'perception' of people and landscapes. In a sample of 344 cardiac arrest survivors, about 12-16% of reported some kind of NDE; of those reporting some form of NDE, approximately 30%, or ~20 out 344 survivors, experienced 'celestial landscapes' or seeing/meeting with a person (van Lommel et al. 2000). To proponents of survival, these experiences are what they appear to be -- real landscapes inhabited by real people.

However, like all of the other elements of the NDE, the 'perception' of deceased people and celestial landscapes are reproduced, often with striking similarity, in a number of pathological conditions. Such phenomena dramatically illustrate the capability of the brain to generate entirely compelling, yet 'false,' perceptions of people and landscapes. The two pathological conditions I want to talk about in this post are Charles Bonnet Syndrome, and DMT intoxication.

Charles Bonnet Syndrome

<a href="http://www.geocities.com/franzbardon/CharlesBonnetSyndrome_e.html" target="_blank">Charles Bonnet syndrome</a> is characterized by CVHs in visually impaired (e.g. macular degeneration or diabetic retinopathy) but psychologically 'normal' people. CBS patients are not delusional, and they understand that their hallucinations are not real (though they seem real). However, if you ask CBS patients whether their hallucinations are more or less vivid than normal visual perception, they will usually say that they are more vivid and detailed (e.g. ffytche et al., 1998).

CBS presents a unique opportunity for studying the neural basis of visual hallucinations, because in CBS the visual hallucinations occur in isolation rather than in association with auditory hallucinations, delusions, etc. Some general information on CBS:

<a href="http://www.telegraph.co.uk/health/main.jhtml?xml=/health/2002/04/08/hdacre08.xml" target="_blank">'Now I know all about ghosts'</a> A british historian describes his CBS hallucinations.

<a href="http://www.100megsfree4.com/farshores/nsee.htm" target="_blank">Seeing is not beleiving</a>

<a href="http://www.rnib.org.uk/info/cbsfin.htm" target="_blank">Charles Bonnet Syndrome</a> General info.

<a href="http://www.rcophth.ac.uk/congress/eliz_thomas_vishalluc.html" target="_blank">Visual Hallucinations in Age-Related Macular Degeneration </a> Describes the research of Dominic ffytche.

Aside from geometric patterns such as lattice or brickwork (tessellopsia), the most common types of hallucination in CBS are figures or isolated faces, usually of unfamiliar people, often with strange facial features such as large eyes. Animals are also quite common, for instance, cows, dogs, or cats. Less common is visual perseveration (palinopsia), in which a visual image is 'retained' in the field of vision. Burke (2002) argues that CBS is caused by 'deafferentation excitation.' Basically, the loss of input from the eyes leads to an excitation of brain activity in the region which is been "deafferented" or disconnected from normal visual signals coming from the eyes (afferent signals). According to ffytche (2001):

Quote:

Overall, the balance of activity in any cortical region is governed by the relationship between cortical inhibitory and cortical excitatory processes. Cutting off the excitatory supply, or deafferentation of the cortex, will produce spontaneous activity. Therefore, any lesion anywhere from the eye itself along the visual pathway that deafferents the visual cortex will lead to spontaneous activity.

<a href="http://www.rcophth.ac.uk/congress/eliz_thomas_vishalluc.html" target="_blank">Visual Hallucinations in Age-Related Macular Degeneration </a>

ffytche et al. (1998) investigated the neural basis of CBS hallucinations using functional magnetic resonance imaging (fmri). They showed that the hallucinations result from increases in activity in the visual cortex, the -outer-bottom-rear portion of the brain, the ventromedial occipital cortex. Discrete hallucinations result from phasic increases in activity, but only when the increases passes a certain threshold. The fMRI data show that the rise in activity producing the hallucination starts well before the conscious experience of the hallucination.

Quote:

An unexpected finding was the rise in fMRI signal before the onset of the conscious experience, the opposite of the normal delayed response to visual stimulation found in fMRI experiments 10,11 . Patients described the appearance and disappearance of their hallucinations as sudden (< 1 s), all-or-nothing phenomena, so the observed �reversed� delay is not an artifact of uncertainty as to when to report the experience.

More significantly, ffytche et al (1998) show that the content of the hallucinations is correlated with the region that is activated. For instance, hallucinations of faces are caused by an an increase in activity in just those regions of the visual cortex that are involved in perception of faces.

Quote:

We found a striking correspondence between the hallucinatory experiences of each patient and the known functional anatomy of the occipital lobe. In patients who hallucinated in color, activity was found in the fusiform gyrus in an area corresponding to the color center, area V4 (mean x = �28,y = �79, z = �16, see refs 13, 14), whereas in the patient who hallucinated in black and white, the activity was outside this region (posterior extent of y = �82, max z = �12, see ref 14).

The descriptions of featureless colors in the hallucinations are similar to the descriptions given by patients whose ventro-medial occipital cortex has been stimulated directly 15 . In the patient who hallucinated an unfamiliar face, additional activity was found in the left middle fusiform gyrus, an area that responds to unfamiliar face stimuli (mean x = �35, y = �63,z = �10, see ref 16). In patients who hallucinated brickwork, fences and a map, activity was found around the collateral sulcus, an area that responds to visual textures 11 . Finally, in the patient who hallucinated objects, activity was found in the middle fusiform gyrus, an area that responds to visually pre-sented objects 17,18 . These results are, to our knowledge, the first evidence of a correlation between the location of activity within specialized cortex and the contents of a hallucination.

Interestingly, Paulig and Mentrup (2001) document the successful treatment of an 81 year-old female CBS patient who experienced "a daily and repetitive occurrence of images predominantly showing human beings such as medieval women and knights in bright colours," and "tiny homunculi strolling on the floor and climbing on her legs when she tried to step on them." After experiencing these hallucinations for 2 years, she was given gabapentin, which brought full remission within 2 days.

DMT intoxication

DMT is the most potent psychedelic drug known. It is either smoked or injected, and the effects last about 20-30 minutes. The effects include more or less complete loss of bodily control, along with vivid visions with eyes both open and closed. Users often describe leaving their bodies and finding themselves in the midst of some type of novel landscape. Auditory hallucinations often occur, and are the same as those most often reported from near-death experiences, ringing or buzzing. Users, especially first-time users, often believe that they are dying or have left their bodies during the experience. At moderate to high doses, the experience is almost always described as 'profound,' strange, astonishing.

From 1990 to 1994, psychiatrist Rick Strassman of New Mexico's School of Medicine conducted several hundred DMT administrations with dozens of human subjects. The results are published in journal articles, and in his book DMT: The Spirit Molecule. A good account of the subjective effects of DMT is provided by Strassman's article <a href="http://www.maps.org/news-letters/v03n2/03208dmt.html" target="_blank">Subjective effects of DMT and the development of the Hallucinogen Rating Scale. MAPS 3(2) Spring 1992,</a> which describes the effects of IV doses of 0.04, 0.1, 0.2, and 0.4mg/kg. At high doses, DMT produces experiences that are described as being similar to near-death experiences, without being identical.

But the really interesting thing about the DMT experience, as opposed to ketamine, LSD, mescaline, and psyilocybin, is the frequency with which users report experiences of 'entitities.' The entities have been described as aliens, elves, insectoids, reptoids, and in other ways. Or they are described as indescribable. The beings may be perceived to be indifferent, benevolent, or ominous. They often 'communicate' nonverbally. The chapter of Strassman's book discussing these 'contact' phenomena is available online in PDF format (<a href="http://www.rickstrassman.com/dmt/contact.pdf" target="_blank">Contact through the veil</a>). Strassman writes:

Quote:

I was neither intellectually nor emotionally prepared for the frequency with which contact with beings occurred in our studies, nor the often utterly bizarre nature of these experiences. Neither, it seemed, were many of the volunteers �even those who had smoked DMT previously. Also surprising were the common themes of what these beings were doing with so many of our volunteers: manipulating, communicating, showing, helping, questioning. It was definitely a two-way street.

As strange as the reports that follow are, our 1990s research was not the first in the scientific literature to describe DMT-induced �contact.� There also are reports from the 1950s quoting volunteers to that effect.These older DMT cases are remarkable in their foreshadowing of the stories we were going to hear almost forty years later. What is even more striking is that I have been unable to locate any similar reports in research subjects taking other psychedelics. Only with DMT do people meet up with �them,� with other beings in a nonmaterial world.
. . .
There are surprising and remarkable consistencies among volunteers� reports of contact with nonmaterial beings. Sound and vibration build until the scene almost explosively shifts to an �alien� realm. Volunteers find themselves on a bed or in a landing bay research environment,or high-technology room. The highly intelligent beings of this �other� world are interested in the subject, seemingly ready for his or her arrival and wasting no time in �getting to work.

The parallels to the NDE are pretty obvious, though there are clearly significant differences as well. Below are more articles containing descriptions of the DMT 'contact' experiences. The quality of the descriptions vary greatly, however. Oh, and I hardly endorse the claims promoted by many of the authors regarding the ontological status of the DMT landscapes or entities.

<a href="http://serendipity.magnet.ch/dmt/dmtart00.html" target="_blank">Apparent Communication with Discarnate Entities Induced by Dimethyltryptamine (DMT) </a>

<a href="http://leda.lycaeum.org/Trips/DMT_at_Reggae_on_the_River.8474.shtml" target="_blank">DMT at Reggae on the River</a>

<a href="http://leda.lycaeum.org/Trips/A_DMT_injection_turns_into_a_"hellish"_experience. .8464.shtml" target="_blank">A DMT injection turns into a "hellish" experience.</a>

<a href="http://leda.lycaeum.org/Trips/Welcome_to_the_Fun_House.5075.shtml" target="_blank">Welcome to the Fun House</a>

<a href="http://leda.lycaeum.org/Trips/Then_came_the_"elves".6591.shtml" target="_blank">Then came the "elves"</a>

Quote:

It was beautiful. All kids of indescribable movements and interlocking patterns were appearing in front of me, and the patterns seemed to stretch out toward me. It seemed to turn into a tunnel formation, and the tunnel not only appeared in front of me, it WAS me. I was this tunnel, my mind and body existed no longer. The tunnel stretched and stretched, with remarkalbe blues and greens appearing very grainy-like, yet very solid at the same time. Then suddenly, I experienced a "sucking" feeling, that I can only describe as my soul being completely pulled from my body and placed somewhere totally new. The roaring sound disappeared completely. All was white (if that's what you call it)

. All was calm. It was like I had just experienced the Big Bang from a first 'person' point of view. Things stared to materiailze in front of me, like gigantic multicolored blankets of smoked (kinda like smoke bombs) were unfurrled in front of me. Every time another blanked unrolled, I heard what I can only describe the sound of a mighty trumpet being blown. These blankets of smoke were creating a totally new universe in front of me. It was truly amazing. This world was being created so fast that I could no longer seperate one blanket/trumpet sound from another. Eventually the whole world was formed in front of me. It was full of the brightest, most intense pastel colors I had ever experienced. Everything was dripping, swirling, meshing into everything else.

Then came the "elves." They didn't look like elves at all.. But they could communicate and turn themselves into anything they wanted. In their true state, they looked kinda like the effect you get when you take several colors of playdough and mix them all together into a single blob. These blobs would bounce around and create new blobs from themselves. They could turn into anything (and of course the things they turned themselves into were like nothing of this world). I saw the most indescribably beautiful "objects" here. I was fascinated. The 'elves' seemed to want me to do the same thing that they were doing. It was frustrating. I couldn't do what they were doing no matter how hard i "tried" to.

<a href="http://serendipity.magnet.ch/dmt/dmtart05.html" target="_blank">Personal reports.</a>

Quote:

I saw a tunnel, which I flew down at great speed. I approached the end of the tunnel, which was closed by two doors on which was written THE END. I burst through these and was carried up through seven heavens, breaking through each one in turn. When I emerged at the top I was flying over a dark landscape (it seemed to be Mexico). I felt that this was all so weird that I should be scared (perhaps I had died), but I did not feel scared. I continued to fly on, over a ravine, leading up to a mountainside, and eventually saw a campfire. As I approached this, cautiously, I saw that on the other side of the fire was a human figure wearing a sombrero, whom I intuitively knew to be don Juan. He invited me to come closer, and spoke to me.

<a href="http://home.freeuk.com/rooted/amydmt.html" target="_blank">Amy's DMT trip.</a>

References

Burke, W. The neural basis of Charles Bonnet hallucinations: a hypothesis. J Neurol Neurosurg Psychiatry 2002 Nov;73(5):535-41.

<a href="http://www.nature.com/cgi-taf/DynaPage.taf?file=/neuro/journal/v1/n8/abs/nn1298_738.html" target="_blank">Ffytche et al., 1998. The anatomy of conscious vision: an fMRI study of visual hallucinations. Nature neuroscience 1, pp. 738 - 742.</a>

<a href="http://www.nature.com/cgi-taf/DynaPage.taf?file=/neuro/journal/v3/n1/abs/nn0100_80.html" target="_blank">Hoffman and Haxby, 2000. Distinct representations of eye gaze and identity in the distributed human neural system for face perception. Nature neuroscience 3, pp. 80-84. </a>

<a href="http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v392/n6676/abs/392598a0_r.html&dynoptions=" target="_blank">Epstein and Kanwisher, 1998. A cortical representation of the local visual environment. Nature 392, pp. 598-601. </a>

<a href="http://www.jneurosci.org/cgi/content/abstract/17/11/4302" target="_blank">Kanwisher et al., 1997. The Fusiform Face Area: A Module in Human Extrastriate Cortex Specialized for Face Perception. Journal of Neuroscience 17, pp. 4302-4311.</a>

<a href="http://jnnp.bmjjournals.com/cgi/content/full/70/6/813" target="_blank">Paulig and Mentrup, 2001. Charles Bonnet's syndrome: complete remission of complex visual hallucinations treated by gabapentin. J Neurol Neurosurg Psychiatry 70, pp. 813-814 .</a>

van Lommel, P., et al., 2001. Near-death experience in survivors of cardiac arrest: a prospective study in the Netherlands. The Lancet 358: 9298.

sweep · 11-29-2002, 01:21 PM

a fascinating read. what about ears then? Do they still work during an NDE or a DMT experience? I know my ears influence my dreams when I am asleep.

Marduk · 11-29-2002, 01:30 PM

In the book “The Way of the Shaman” experiences similar to those with DMT are also reported, encounters with strange ‘beings’ who will answer questions. Most often reported is a two headed snake. Who after deriding you for entering his ‘realm’ will begrudgingly answer one and only one question. The author asked the snake what he was doing there? His reply “hiding”. However the substance wasn’t DMT but a psychedelic root. (perhaps containing DMT, can’t remember the name) The shaman claim this is how they acquire their various recipes for herbs and natural medicines they use to treat their ‘patients’.

Maybe ancient shaman used this same root, ever notice how the ancient 'gods' all have various combinations of human and animal heads and such?

[ November 29, 2002: Message edited by: marduck ]

Marduk · 11-29-2002, 01:35 PM

hmmmmmmm, now you've got me thinking. where do you get some of this DMT stuff these days?

Coragyps · 11-29-2002, 01:50 PM

It seems that I remember reading of similar experiences with the alkaloid harmaline, the goody in the South American herb yage. It wasn't on the street in '69, or I could probably report first-hand

. There is a book, long out of print but possibly in a college library, titled "Ethnopharmacologic Search for Psychoactive Drugs" or something real close to that, put out by some agency of the US Government before we hippies even existed, that is likely where I got my info. Harmaline is apparently legal and available through chemical supply houses, though I don't think I'd want the order on my personal credit card.
DMT was damn interesting, but I only ever saw it in small doses on weed. Very visual stuff.

Marduk · 11-29-2002, 01:57 PM

Curse my crummy memory, but there is another powerful psychoactive drug that few people ever take a second time, the effect is that you feel like an inanimate object for several hours.

ps418 · 11-29-2002, 02:44 PM

Quote:

Originally posted by Coragyps:
It seems that I remember reading of similar experiences with the alkaloid harmaline, the goody in the South American herb yage.

If my understanding of the chemistry is correct, harmaline is not the main active ingredient in Yage (aka Ayahuasca, aka the Banisteriopsis caapi vine), but only potentiates the DMT in the plant. DMT is not orally active unless taken with an MAO inhibiter, such as harmaline. I could be wrong though, in that the harmaline may have psychoactive properties of its own.

Aside from mescaline, the active ingredient in most psychedelic plants, especially those used in shamanistic contexts, is DMT. Oddly enough, at least one toad -the Sonoran desert toad, Bufo alvarius-- produces DMT also.

However, plant potions and toad venoms really cannot compare with the intensity of the experience caused by smoking of injecting synthetic DMT. And on the biochemical level, most of the psychedelics (including LSD, psilocybin, DMT, and mescaline) seem to share a common mechanism -- they all act as partial agonists of 5HT2 serotonin receptors, and their hallucinogenic potency is directly related to their relative affinity for these receptors (<a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=651372 5&dopt=Abstract" target="_blank">Glennon et al., 1982;</a> <a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=274294 5&dopt=Abstract" target="_blank">Brazell and Stahl, 1989;</a> <a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=104324 84&dopt=Abstract" target="_blank">Aghajanian and Marek, 1999</a>).

ps418 · 11-29-2002, 03:04 PM

Quote:

Originally posted by marduck:
Curse my crummy memory, but there is another powerful psychoactive drug that few people ever take a second time, the effect is that you feel like an inanimate object for several hours.

Well, the inanimate object part of the description sounds like ketamine, which is an anesthetic, and at high doses will make you inanimate whether you want to be or not.

Coragyps · 11-29-2002, 03:15 PM

Quote:

And on the biochemical level, most of the psychedelics (including LSD, psilocybin, DMT, and mescaline) seem to share a common mechanism -- they all act as partial agonists of 5HT2 serotonin receptors

They're all stereochemically pretty closely related - all of those and a few others can be thought of as beta-phenylethylamines, as can serotonin. Amphetamine and Ecstacy are in this class too, but aren't as hallucinogenic. As a young dopefiend chemistry major, I used to doodle the structure of mescaline as a key - the key to your true mind...

Ah, youth!

ps418 · 11-29-2002, 03:19 PM

Here are a couple more interesting tidbits I found.

Another type of hallucination that sometimes occurs in the NDE is the 'sensed presence' type of hallucination. These are common in hypnagogic and hypnopompic experiences. Neuroscientist Michael Persinger has induced the 'sensed presence' with his magnetic helmet, by stimulating the temporal lobe with a 40hz magnetic signal. I found that they are also fairly common in Parkinson's patients, although whether this is caused by the neurologic degeneration associated with PD -or by the drugs used to treat it- is not clear. Approximately 64% of PD patients report presence hallucinations. Fenelon et al. (2000) write:

Quote:

The patient had the vivid sensation of the presence of somebody either somewhere in the room or, less often, behind him or her. In all cases, the presence was that of a person, and in one case it was also occasionally the presence of an animal (a rat). In seven cases, the presence was that of a relative (deceased in three cases). . . The presence hallucinations were commonly as vivid as a hallucinated scene and were described as a 'perception'' (p. 735).

One patient would frequently have vivid sensations that her sister was in the bed with her, and would actually lift the sheets to check. Another referred to his persistent sensed presence as his 'gaurdian angel.'

Complex visual hallucinations are also noted with PD, including faces and small figures. One woman reported seeing her deceased son, who said 'take care of yourself' (Fenelon et al., p. 737). Usually the patient is aware of the unreality of the visions, but comment that they 'seem so real.'

Fenelon G, et al., 2000. Hallucinations in Parkinson's disease: prevalence, phenomenology and risk factors. Brain 123:733-45.

Manford and Andermann (1998) review complex visual hallucinations resulting from various brain disorders. Some show very interesting parallels to the NDE. For instance, a 58-year old man with reduced blood supply (ischaemia) to the right basal ganglia, right thalamus, and part of the occipital cortex reported dwarves, butterflies, men in suits or victorian clothing. In one instance he saw three dwarves with egg-shaped heads (sounds like an aborted abduction experience!) at the foot of the bed, touching his feet. One of the dwarves had a 'comforting' golden face with blue eyes, and told the patient 'Its all over' (p. 1820).

<a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=979874 0&dopt=Abstract" target="_blank">Manford M, Andermann F., 1998. Complex visual hallucinations. Clinical and neurobiological insights. Brain.121 ( Pt 10):1819-40.</a>

[ November 29, 2002: Message edited by: ps418 ]

11-29-2002, 01:30 PM	#3
Marduk Veteran Member Join Date: Aug 2000 Location: the 10th planet Posts: 5,065	In the book “The Way of the Shaman” experiences similar to those with DMT are also reported, encounters with strange ‘beings’ who will answer questions. Most often reported is a two headed snake. Who after deriding you for entering his ‘realm’ will begrudgingly answer one and only one question. The author asked the snake what he was doing there? His reply “hiding”. However the substance wasn’t DMT but a psychedelic root. (perhaps containing DMT, can’t remember the name) The shaman claim this is how they acquire their various recipes for herbs and natural medicines they use to treat their ‘patients’. Maybe ancient shaman used this same root, ever notice how the ancient 'gods' all have various combinations of human and animal heads and such? [ November 29, 2002: Message edited by: marduck ]</p>

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11-29-2002, 01:21 PM	#2
sweep Senior Member Join Date: Aug 2002 Location: sugar factory Posts: 873	a fascinating read. what about ears then? Do they still work during an NDE or a DMT experience? I know my ears influence my dreams when I am asleep.

11-29-2002, 01:35 PM	#4
Marduk Veteran Member Join Date: Aug 2000 Location: the 10th planet Posts: 5,065	hmmmmmmm, now you've got me thinking. where do you get some of this DMT stuff these days?

11-29-2002, 01:50 PM	#5
Coragyps Veteran Join Date: Aug 2001 Location: Snyder,Texas,USA Posts: 4,411	It seems that I remember reading of similar experiences with the alkaloid harmaline, the goody in the South American herb yage. It wasn't on the street in '69, or I could probably report first-hand . There is a book, long out of print but possibly in a college library, titled "Ethnopharmacologic Search for Psychoactive Drugs" or something real close to that, put out by some agency of the US Government before we hippies even existed, that is likely where I got my info. Harmaline is apparently legal and available through chemical supply houses, though I don't think I'd want the order on my personal credit card. DMT was damn interesting, but I only ever saw it in small doses on weed. Very visual stuff.

11-29-2002, 01:57 PM	#6
Marduk Veteran Member Join Date: Aug 2000 Location: the 10th planet Posts: 5,065	Curse my crummy memory, but there is another powerful psychoactive drug that few people ever take a second time, the effect is that you feel like an inanimate object for several hours.

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