I believe it was Rick Strassman’s research on DMT that found a small percentage of people – around 5% – to be mostly immune to the effects of DMT. I’m wondering if anyone knows or has a theory about why that is?
I’ve been reading some interesting research here (see the last four paragraphs) and here about the possible role of serotonin in the development of both synesthesia, and disorders on the autism spectrum. Is it possible that there is some connection, perhaps one mediated by serotonin or its receptors in the brain, between synesthesia, autism-spectrum disorders, and immunity to DMT? The researchers in the first paper found incidence of elevated serotonin levels in one hemisphere of the brain, and (assumed to be compensatory) reduced levels in the other hemisphere in high-functioning autistic people.
I did manage to find one website asking what hallucinogens were like for people with synesthesia. (I love the internet!) The consensus among a couple of responders seemed to be that synesthetic responses still function in expected ways, even while hallucinating. (i.e., you might hallucinate a number five, but you still associate it with a color or shape)
All the same, since the mechanism of action of many hallucinogens seems to involve a serotonin cascade, I’m wondering if immunity to them may be something to do with deficient or oddly-developed serotonin receptors? Like, if a person had too much serotonin to begin with, perhaps their receptors would be downregulated to the point where a cascade, inducing hallucination, wasn’t supported?
In case you’re wondering why I ask, I have questions about all kinds of things. I’m fighting my ignorance one battle at a time. Some of the battles are weirder than others.
DMT immunity: Was this 5% among people who had been injected or from self-reports? If it’s from self-reports, it’s easy to get little effect from DMT if you don’t administer it properly.
As serotonin, synesthesia and autism-spectrum disorders, I can see some similarities. I’m not sure we know enough about either the neurochemistry of psychedelics of ASD to make more than somewhat educated guesses.
Psychedelics and synesthesia:
Psychedelics activate serotonin receptors (especially 5-HT2A) which reduces activity in the default mode network. The DMN acts as a communication hub between different parts of the brain. It also results in glutamate release which 1) acts as an amplifier 2) creates new neural pathways between regions which typically have little/none, hence synesthesia. In other words, psychedelics reduce activity in the ordinary neural pathways and create & amplify alternative pathways e.g.: neural pathways go straight from the hearing sections to the visual sections which then makes you see sound as shapes & colors.
Psychedelics and ASD:
As said above, psychedelics reduce DMN activity. The main brain network which competes with the DMN is the task positive network. It’s quite likely that autism-spectrum people have a DMN which is less active than usual and a TPN which is more active than usual. This would be consistent with ASD people being less effective than average at social interactions and more likely to have laser-like focus on things/activities.
Also, don’t ASD people tend to get easily overwhelmed by sensory stimuli? This may have to do with higher glutamate presence (as an amplifier) or by their brain not filtering out as much information as non-ASD people. Psychedelics can also result in sensory or perceptual overload by reducing the DMN’s gating of brain activity.
Are ASD people more likely than average to have synesthesia?
It is my understanding that this number was in reference to the subjects who were injected with DMT in the controlled studies. However, I attempted to google it just now, and am not immediately finding a direct cite for that.
So, if I understand what you’ve told me correctly, then perhaps an element I hadn’t considered may be insufficient release of glutamine? (I know you didn’t say that, but it seems to be implied)
If something were amiss with the glutamate “amplifier,” then could that also cause problems with short-term memory?
“glutamate is by a wide margin the most abundant neurotransmitter in the vertebrate nervous system.[1] It is used by every major excitatory information-transmitting pathway in the vertebrate brain, accounting in total for well over 90% of the synaptic connections in the human brain.”
ASD and immunity to DMT may just be unrelated and their combination in the same person may be a coincidence.
Too much or too little glutamate might both produce short-term memory problems. With too little, there is not enough focus. With too much glutamate, it seems that short-term memory gets refreshed/overwritten too quickly.
Its short-term memory and focus-enhancing effects curve likely follows the Yerkes-Dodson law Yerkes–Dodson law - Wikipedia
Oh, wow! Another deep layer. It sounds like what they’re saying in that wiki article is (grossly paraphrased) that if something is too cool or exciting, it is possible that retaining short-term memories of same may be compromised.
MichaelEMouse, I meant to ask you in the last thread you discussed the Default Mode Network in: are there any popular science books that describe this? I was talking to a couple of friends about it the other day and they didn’t want to read journal articles directly :rolleyes: , but they found it interesting enough that they asked if there was a book going into more detail than the Wikipedia article.
I don’t know. Perhaps Marcus Raichle or Judson Brewer have published books about it.
If your friends want to read popular science books, they’ll surely be ok with watching Youtube videos from the specialists involved:
Much appreciated, MichaelEMouse. I’m sure the videos will be quite helpful. I think I checked for books by Raichle the first time I read your post discussing this in the cryonics thread, but I found nothing by him at the time. I’ll check again, and for Brewer. Either way, I will certainly pass on your video links, though, and watch them myself as well. Thanks for taking the time.
Second time you think of it as cryonics. It’s not quite it : )
Even if someone has no interest at all in taking psychedelics, learning about their effects on the brain can be useful for those who would take up meditation. Both piqued my interest when I realized that I felt the same the day after taking shrooms as I had the day after my first good meditation session. I was also surprised that my first time meditating for a full hour left me feeling much the same as on a low dose of MDMA. And Nancy Reagan didn’t say anything about how you shouldn’t do meditation.
More Brewer: https://www.youtube.com/watch?v=wil45EaQvUE
One of the more important parts of that vid is at 46 minutes: thinking of your breath and feeling the sensations of the breath are quite different neurologically. Before seeing the fMRI evidence, I had also noticed that a non-verbal, purely sensory experience of the breath is much better meditation than thinking about it.
Yeah, that was my mistake. I first saw the “default mode network” topic was in a thread on cryonics. I thought it might have been you, but looking back I found the thread and it was actually njtt, not you, that brought it up.