The Guardian headlines on 28 Nov 2017: "Psychedelic drugs induce 'heightened state of consciousness', brain scans show".

Healthy volunteers who received LSD, ketamine or psilocybin, a compound found in magic mushrooms, were found to have more random brain activity than normal while under the influence, according to a study into the effects of the drugs.

Researchers at the University of Sussex and Imperial College, London, measured the activity of neurons in people’s brains as the drugs took hold. Similar measurements have shown that when people are asleep or under anaesthetic, their neurons tend to fire in a more predictable way than when they are awake.

“What we find is that under each of these psychedelic compounds, this specific measure of global conscious level goes up, so it moves in the other direction. The neural activity becomes more unpredictable,” said Anil Seth, a professor of neuroscience at the University of Sussex. “Until now, we’ve only ever seen decreases compared to the baseline of the normal waking state.”

The research, published in the journal Scientific Reports, appears 74 years to the day after the Swiss chemist Albert Hoffman went on the world’s first LSD trip.

After the Guardian article just gets into a long expose of Hoffman's experience. But it does seem to identify one of the authors a bit later on:

Robin Carhart-Harris, a researcher at Imperial College who took part in the study, said the sudden increase in randomness in brain activity appeared to reflect a deeper and richer conscious state.

“People tend to associate phrases like ‘a higher state of consciousness’ with hippy speak and mystical nonsense. This is potentially the beginning of the demystification, showing its physiological and biological underpinnings,” he said. “Maybe this is a neural signature of the mind opening.”

N.B. a quick search found a TEDx talk by Carhart-Harris on the topic, but it seems older than this study. Also an older (2014) headline: "Dr Robin Carhart-Harris is the first scientist in over 40 years to test LSD on humans - and you're next".

So I have some questions:

  • Can anyone locate this Scientific Reports study?
  • Has there been any more skeptical commentary on it? Or is there (silent) agreement that it really proves psychedelics induce a heightened state of consciousness?

Based on a photo credit to Muthukumaraswamy in that Guardian article, I found a 2016 paper "Increased Global Functional Connectivity Correlates with LSD-Induced Ego Dissolution" co-authored by many, including Muthukumaraswamy and Carhart-Harris, but it was in Current Biology, and the finding don't quite match, although they are somewhat related; the focus of this paper is a bit different "ego dissolution" etc.

There's also a paper in Scientific Reports published around a month before the Guardian article "Psilocybin for treatment-resistant depression: fMRI-measured brain mechanisms", on which Carhart-Harris is lead author, but it doesn't ever mention consciousness--except in the title of a [self-]citation (from 2014)... "The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs", which was later (2016) commented upon by David Papo. But I don't see the "heightened" claims in either of these... however they do debate the

“entropic brain hypothesis” [which] holds that the quality of conscious states depends on the system's entropy

which might be the same thing; I'll have to read these in detail to figure that out. Still, is there a Sci. Rep. paper with additional evidence as the Guardian article seems to suggest?

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