Turn Off, Tune In, Drop Out

In the February 25 Issue:

Turn off, tune in, drop out

Magic mushrooms reduce blood flow to parts of brain

By Devin Powell

February 25th, 2012; Vol.181 #4 (p. 8)

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When Timothy Leary advised his generation to “turn on” by taking psychedelic drugs, he got it all wrong. Turning off parts of the brain may be the real secret to expanding your mind, a new study of hallucinogenic mushrooms finds.

The study is the most detailed look yet at where and how psychedelics work in the human brain, says psychiatrist and neuropsychopharmacologist David Nutt of Imperial College London, whose team reports the findings online January 23 in the Proceedings of the National Academy of Sciences.

Nutt and colleagues recruited 15 people with previous experience taking hallucinogens. Each was injected with a small amount of psilocybin, the ingredient responsible for magic mushrooms’ mind-bending properties. The effect was immediate, peaking in just minutes and lasting for about an hour.

Before and after the volunteers tripped out — one described the experience as “dissolving,” another as “kneeling at the foot of God” — their brains were scanned. These measurements revealed decreases in the amount of blood flowing through parts of the volunteers’ brains. Surprised by the result, the researchers repeated the experiment with another group, using a different scanning technique. The same pattern of reduced activity emerged, most pronounced in the hubs that connect different parts of the brain — including the thalamus and parts of the cingulate cortex.

“The findings are astounding and are going to completely change how we understand the action of hallucinogens,” says psychiatrist and pharmacologist Bryan Roth of the University of North Carolina at Chapel Hill, who was not involved in the study. “They’re the complete opposite of what has been predicted.”

Previous studies suggested that hallucinogens stimulate certain kinds of neurons in mice. Nutt expected to see an uptick of activity in the visual regions of the brain, which would explain the kaleidoscopic hallucinations often experienced by magic mushroom users.

But suppressing core regions that help to coordinate and control the brain could have deeper, more philosophical consequences. It fits with how Aldous Huxley described the effects of mescaline — a hallucinogen that, in his words, flung wide the “doors of perception.”

“Decreasing the activity in certain hubs in the network may allow for a more unconstrained conscious experience,” says Matthew Johnson, an experimental psychologist at Johns Hopkins University School of Medicine in Baltimore who studies psilocybin and other hallucinogens. “These drugs may lift the filters that are at play in terms of limiting our perception of reality.”

Further work by Nutt’s team showed that the brain hubs responded together, linked by a neural circuit called the default mode network. Some scientists believe this highly interconnected brain superhighway is essential for maintaining a person’s sense of self.

Putting the brakes on this network could help to treat certain psychological conditions by opening the brain to new ways of thinking, researchers hope. Several studies have shown that psilocybin can change people’s attitudes for the better and may be useful for treating depression, a condition linked to too much activity in the default mode network.

“Chemically switching off might have very profound beneficial effects,” says Nutt, who suspects that psilocybin could also be useful for treating obsessive-compulsive disorder. “It may help people completely locked into a mindset that drives their lives.”

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Comments 4

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In the early 60s two separate clinical trials were published involving LSD and psilocybin therapy on severly autistic and schizophrenic children. The patients were at life threatining stages in their disorders and had not responded to other avenues of treatment. The outcomes were nothing short of miraculous. In several of the worst cases the children were able to attend public schools within two years of the experimental treatment's start.
Other clinical studies with alcoholics in Canada also provided positive results not seen with conventional treatments.
An excellent online resource for literature in this area is the website "psychedelic library".
It is very unfortunate that such a very promising line of study was aborted in the mid 60s due to irrational fear and political pressure.

Harold Snellen

Jan. 25, 2012 at 9:18am
It's pretty disconcerting that when you use the highly judgmental and scientifically inappropriate term of "tripping out" when referring to the subjects' experiences during this trial. These trials were conducted with very small doses of psychoactive materials on experienced users... under close control.

These drugs have incredible potential for psychotherapy and don't need to have stereotypes and judgement furthered by those charged with reporting facts... leave the hippie references to CNN.

I've seen more sane, lucid thought from people on psilocybin and LSD than those on mass-marketed pharmaceuticals. I've also seen people's emotional and mental states improve dramatically from responsible use of these substances, and the exact opposite from pharmaceuticals (Xanax, anyone?).

I agree with Harold, that it's a shame these lines of study are halted by antiquated, puritanical fears. Especially with the rampant over-prescription and abuse of pills.

Andi G

Jan. 26, 2012 at 10:06am
Thanks to Leary, there are now enough people who know the truth about psychedelics to allow organizations like MAPS to exist. The League for Spiritual Discovery seems to be making a comeback too. ("Spiritual but not necessarily religious.")

Timothy Long

Jan. 30, 2012 at 9:21am
Contrary to what is suggested by this article, the reduced amount of blood flow to the brain will make more harm than good as, all those who are working/using the brain activity as a signature for behavioural problems, like depression, know that decreasing brain's activity, as shown by measures like low EEG, is typical of depression and other mental problems. This is why some of those who take psilocybin experience bouts of mental problems afterwards, and in some case suicide feelings.

Jorge Alvoeiro

Jan. 30, 2012 at 4:02pm

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