Heat map of brain activity patterns shows profound disturbance during an individual’s experience after taking psilocybin. Photo: Washington School of Medicine
The effects of psilocybin on the brain are "shockingly large" a new Washington University School of Medicine study has found.
Psilocybin is the active compound in magic mushrooms and for the study, seven people were given doses of the psychedelic drug, and then had their brains scanned by MRI.
The resulting heat map showed the drug desynchronising certain brain networks, and potentially enhancing its plasticity - with profound potential therapeutic applications.
This work adds to efforts to harness psilocybin's potential to treat some forms of mental illness.
Neurologist Dr Nico Dosenbach, worked on the study and was also a participant, he told RNZ's Saturday Morning.
Being in the MRI scanner as the psilocybin took hold was a strange experience, he said.
Nico Dosenbach: how psilocybin changes the brain
"The way we do these scans is you look at a black screen which has a tiny little white plus sign on it, and the plus sign started turning into rainbow colours and melting, like an oil slick on top of a puddle.
"Sometimes your vision gets blurry if you're in there for hours and hours just staring at the little white plus, but that's when I knew I this is not [control drug] Ritalin."
His sense of time melted away, he said.
"One of the reasons I couldn't resist participating in this study was, whenever I talked to people that this concept of ineffability or something you can't describe as words, I also really wanted to see what it's like.
"And, at some point my sense of self disappeared, which sounds silly, and it was simultaneous when my sense of time and space also disappeared, which makes sense in terms of the brain organisation, those computations are run by the same or similar circuits."
As a neurologist it was fascinating, he said, to "look behind the curtain".
Dr Nico Dosenbach. Photo: Supplied / Dr Nico Dosenbach
"You can remember what happened, even though your brain function is so distorted. With most drugs, if your abilities get this distorted, you lose memory, because your memory systems are very finicky, like with benzodiazepines, alcohol.
"So that's special for psilocybin and if you're a neuroscientist, it's super fascinating to be able to remember all the completely distorted thoughts you were having."
The scans showed the effect of psilocybin on the brains of participants was "shockingly" large, he said.
"Normally, when we do an experiment and try very hard, we need a lot of statistics and maths to get a minuscule effect back. And this was an elephant compared to a mosquito.
"Shockingly large, a much, much stronger effect than I expected, which, in retrospect, fits with the subjective experience."
Brain connectivity patterns were stable and unique to the individual, he said.
"On psilocybin at the peak effect on all the brains, the way they were organised or connected, we called it the psychedelic dimension, these have all changed in a similar way, but they all became more similar to each other.
"At that point on psilocybin, I was more similar to other people's brains on psilocybin than my own brain not on psilocybin, which was very unexpected. That was a shock."
During those few hours on the psychedelic, the brain was completely re-arranged and then retuned to normal, he said.
"The biggest effects were on what we call the default mode network, which is the introspective or self-referential memory, and also time and space, and that's also where the participants reported the biggest effects, time dilation, loss of sense of space, and then ego death, or no longer feeling like you're you."
So what are the possible therapeutic applications to be drawn from the research? Treatment resistant depressions is on contender, he said along with conditions such as PTSD.
"It probably won't be magical for everyone, for everything, but I do think, and I'm not the only one, many, many psychiatrists and researchers in this area think the same way that it has significant potential to be an option for some people who really are out of other good options."