The funny thing is even with resting-state, there are increased top-down/decreased bottom-up effects (doi.org/10.1038/s413..., doi.org/10.1016/j.eu...) or bidirectional increases (doi.org/10.1016/j.ne...), but of course REBUS heads don't acknowledge this 🤷🏾
We have enough resting-state data & they'll eventually be shared so I'm advocating for theory-driven task-based studies where we constrain the inference space, see how the brain solves problems differently on psychedelics, & find real cognitive enhancements on psychedelics. 15/15
Bc of this nebulous comparison that doesn't tether brain activity to mental states, there have unfortunately been a lot of bizarre reverse inferences (inferring mental activity from the brain despite brain activity from fMRI being able to show up under several conditions). 14/15
But it’s also a problem w/placebo when >40% of people fall asleep sciencedirect.com/science/arti.... What do differences in brain coupling even mean when comparing people falling asleep to people under drugs preventing sleep doing things that may not even be unique to psychedelic fx? 13/15
A potential issue is resting-state fMRI (i.e., people do whatever they want in the scanner). This is a problem w/psychedelics when people may especially be engaging in incomparable cognitive operations (remembering their mom, getting paranoid, paying attention to visuals)…12/15
If you look at the distributions above, the blue and orange curves (psilocybin & LSD) are the slimmest bc they have the most data so they're most comparable & they largely overlap. But if psychedelic effects were so similar, we’d expect far less variability between drugs. 11/15
However, Fred points out here that there were differences. The truth is we couldn’t properly test for differences bc there wasn’t enough data for most drugs & differences could be explained by various differences between studies. 10/15
bsky.app/profile/fred...
We've even found similarities between the effects of different 5-HT2A psychedelics on various memory processes.
doi.org/10.1037/rev0...
doi.org/10.1016/j.bp...
doi.org/10.1007/s402...
9/15
Third, this article says psychedelics all act “surprisingly” similar. The similarity isn't surprising when all drugs tested primarily act through 5-HT2A & have similar subjective fx w/many differences explained by dose or route of administration. nature.com/articles/d41...
8/15
There was also evidence for increased coupling between the thalamus & cortex as well as cortex & caudate, which is consistent with prior work and the first systems-level model proposed by Mark Geyer & Franz Vollenweider (CSTC/thalamic gating, www.sciencedirect.com/science/arti...). 7/15
The increases in between-network coupling were also far less stark than past work, including unreliable fx between different high-level networks. Instead, there was some selective evidence for increases between high-level and sensory networks. 6/15
Regarding the DMN, the only robust effect seemed to be in the C subnetwork, which is not the classic “self-referential” DMN but rather regions in the medial temporal lobe involved in memory. 5/15
Brain areas that normally sync up to form networks are syncing less, & separate brain networks are now syncing more. But that’s not what was found here. The Bayesian analysis found within-network fx were rather selective, many being unreliable/dependent on analytic methods. 4/15
Second, Robin claims these effects are familiar, alluding to his past work but this isn’t exactly true. What he’s referring to are decreases in within-network coupling (the famous “DMN disintegration”) & increases in between-network coupling, meaning…3/15
x.com/RCarhartHarr...
First, this video referring to our work as using “AI" when we used Bayesian hierarchical regression (& AI is never mentioned in the paper). Also I don’t think anyone is testing prototypical psychedelics in schizophrenia (tho there’s a study w/MDMA). 2/15
x.com/Mila_Quebec/...
Now that it has been out for a week, I thought I’d address a few strange takes regarding our recent mega-analysis on the effects of psychedelics on brain function (specifically, resting-state functional connectivity). 1/15
www.nature.com/articles/s41...
I'll be giving a talk on psychedelics & memory via Zoom tomorrow. You can register for it here:
open-foundation.org/events/onlin...
“Psychology” is far less interesting than “consciousness.”
This paper has been a long time coming. Instead of reanalyzing the same old resting-state fMRI datasets, we combined nearly all datasets around the world. Note that we didn't exactly find indisputable evidence for "default mode network disintegration."
www.nature.com/articles/s41...
Just reviewed my first paper written by AI! Shame on not only the first author but the relatively long list of authors who didn't realize this🤦🏾
The hardest part of science is posing the right question, not answering it.
The boys got something cooking… @hamiltonmorris.bsky.social
Anyone who thought that resting-state somehow provided a privileged baseline rather than a lazy convenience 🤦🏾♂️
@samcooper.bsky.social has a soon-to-be released, easy-to-edit fear conditioning/extinction paradigm in PsychoPy called ITEC.
Shouldn’t be surprising coming from someone who has argued in publications that psychedelics should be studied with resting-state because of Heisenberg’s uncertainty principle 😂
We're still running this survey w/the Center for MINDS investigating factors that produce tangible creative insights from psychedelics. We unfortunately received >10k responses from bots, so we're no longer providing payment, but your responses will help science!
tiny.cc/Psychedelics...
Recent Chacruna article in which I discuss the potential memory distorting effects of psychedelics and upcoming work from my lab:
chacruna.net/the-tangled-...
I think this is good for all of us doing basic science research in humans with psychedelics and other drugs (no more clinical trial registration):
grants.nih.gov/grants/guide...
We're still running this survey w/the Center for MINDS investigating factors that produce tangible creative insights from psychedelics. We unfortunately received >10k responses from bots, so we're no longer providing payment, but your responses will help science!
tiny.cc/Psychedelics...
Check out the recent episode of the Entrepreneurs in Recovery Podcast in which I chat with Jesse Harless about psychedelics and memory.
YouTube: youtu.be/h7HCyv2MR7s
Spotify: open.spotify.com/episode/3CxY...