Tip-toeing towards the question ‘What is consciousness?’

I do not know what ‘it’ is. No one does, quite yet.

Robin Carhart-Harris (PhD) and Professor David Nutt are both from Imperial College London and are very much interested in answering that question. You may have heard of Professor Nutt back in 2009 when he was sacked from his position as a drug advisor to the British government, for doing just that — communicating his understanding of drugs. So be it.

Both scientists describe their approach to the study of consciousness like this:

Perturbing a system and observing the consequences is a classic scientific strategy for understanding a phenomenon. Psychedelic drugs perturb consciousness in a marked and novel way and thus are powerful tools for studying its mechanisms [PMID: 24904346]

It’s straightforward, unassuming and an exciting way to study humans. Before we dive in, here is a quote (from their main paper discussed below) I can’t resist and a little information on one of their favorite tools for ‘disturbing the pond’ that is consciousness, namely Magic Mushrooms.

It does not seem to be an exaggeration to say that psychedelics, used responsibly and with proper caution, would be for psychiatry what the microscope is for biology and medicine or the telescope is for astronomy. These tools make it possible to study important processes that under normal circumstances are not available for direct observation (Grof, 1980)

A little information

2 ingredients in these shrooms can introduce you to dancing donuts. They are psilocybin and psilocin. Dry magic mushrooms contain anywhere from 0.2% to 1% of both compounds by weight. When psilocybin is fiddled with (aka dephosphorylated) it becomes the active metabolite, psilocin. In 1962 Wolback et al. said that “an equimolar dose to 1mol of psilocin is 1.4mol of psilocybin”. I’ll take their word. Funny how both compounds travel together. They have “predominant agonist activity on serotonin 5HT2A/C and 5HT1A receptors” [PMID: 24444771]. Why do you care? Because “5HT2A receptor agonism is considered necessary for hallucinogenic effects” [PMID: 24444771]. Damn straight it is! By the way – who better than Albert freakin’ Hofmann to isolate, identify and synthesize both compounds back in the early 60s? Thanks man! Magic mushroom use dates back about 3,000 years, in Mexico. They were and are still used far and wide for medicinal and non-medicinal purposes. They have a very low toxicity level and they are certainly not neurotoxic. Let’s explore that further. How does psilocybin compare to other molecules like natural vitamins, or over-the-counter drugs? We could look at it like this:

The lethal dose killing 50% of a population is called the LD50.The therapeutically effective dose for 50% of a population is called the ED50. The LD50/ED50 ratio is the therapeutic index of a drug. It tells you at what dosage a drug will exert its therapeutic effect on 50% of a population. So to put things into perspective, for shrooms “the LD50/ED50 ratio is 641 […] (compare this with 9637 for vitamin A, 4816 for LSD, 199 for aspirin and 21 for nicotine)”[PMID: 24444771]. Captain Obvious says it is very much safer than most over-the-counter drugs. Same goes for the many plant compounds found in your typical health foods store.

You want to know how shrooms compare to what your step-brother’s second cousin took back-packing across Asia? Well, psychonauts would be right to point out that “psilocybin is 45 times less potent than LSD and 66 times more potent than mescaline”[PMID: 24444771].

Onwards! Nutt and Carhart-Harris also employ MDMA (aka ecstasy) to probe consciousness. It is a drug belonging to the class of phenethylamines and amphetamines. Its empathogenic effects are of great interest in the treatment of various psychiatric disorders. However, it appears less suited to the study of consciousness when compared to the ‘classic psychedelics’ like LSD or magic mushrooms. The reason is simple. The shift it produces away form normal consciousness isn’t as dramatic. Don’t get me wrong, a lot of trippy-dippy stuff will still happen to you — just not quite in the same vein as a true psychedelic experience.

This is their paper that made me stand-up and take notice of neurosciences progress in the study of consciousness (clap clap). It should really be read in its entirety as it’s more of a scientific tour de force than any old paper:

The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs [PMID: 24550805]

Let’s unpack this. Entropy, simplistically, is measure of disorder. In this brainy context it refers to the degree of randomness or uncertainty of a self-organized complex system.

Concept of Entropy

Our cerebral, self-organized complex networks are “functionally and structurally connected brain regions that show high spontaneous or ‘on-going’ metabolism”. Like a truck idling. These are described as DMNs (Default Mode Networks). Their resting-state functionality (RSFC) simply refers to the “temporal correlations between spatially distinct neurophysiological events” that characterize them during task-free states (like lying down with your eyes closed or sitting still). This is equivalent to describing the typical noise and pitch of an idling truck. When you focus on tasks or achieving goals, the DMN deactivates somewhat. In the metaphor, the truck changes what it’s doing, it is now in gear and driving.

Our brains have the kinds of systems that always teeter back and forth in a non-equilibrium state (i.e. it’s not sitting stably at the bottom of a metaphorical trough or valley but constantly adjusting, fidgeting). Typical of non-equilibrium systems, our brains display self-organized criticality (SOC). This means they naturally move towards a ‘critical’ point, situated at a weird intersection where states transition between order and disorder.

What does this mean when you eat a magic mushroom? Basically, you increase the entropy within those systems. There is “evidence that the brain exhibits more characteristics of criticality in the psychedelic state than are apparent during normal waking consciousness”. Remember, for our purposes criticality is where stuff gets weird and interesting. You brush shoulders with either extremes of the range granted by your non-equilibrium networks. Let’s put this into perspective with other life forms. I apologize in advance to any non-homo sapiens sapiens readers out there for the following passage:

the human brain exhibits greater entropy than other members of the animal kingdom, which is equivalent to saying that the human mind possesses a greater repertoire of potential mental states than lower animals

Booya! In your FACE pandas! [composes himself]

Carhart-Harris and Nutt proposes that we did not arrive at the consciousness we have by ‘taming’ it (entry suppression). Rather, we may have ‘challenged’ it (entropy expansion). This means the disorder of our brain systems increased compared to other animals. Only after that did we resort to entropy suppression (reorganizing, settling). This is the state we are currently purported to be in. This is the state that can be messed with.

To understand our consciousness subjectively, in experiential terms, we need to identify and define that which is being changed or played with: the ego. Freud’s ego, actually, which is “a sensation of possessing an identity or personality; most simply, the ego is our ‘sense of self’ […] Effectively, the terms ‘ego’ and ‘self’ are synonyms, except that ‘the ego’ has a background in Freudian metapsychology [where it] is not just a (high-level) sensation of self-hood; it is a fundamental system that works in competition and cooperation with other processes in the mind to determine the quality of consciousness”. Sorry for the long quote but definitions are important in science.

This paper proposes an Entropic Brain Hypothesis.

Primary consciousness = unconstrained cognition, less ordered (higher-entropy) neurodynamics.

Secondary consciousness = constrained cognition, more ordered neurodynamics, giving us an evolutionarily advantage balancing order and disorder, which might be more or less perfectly ‘critical’.

Driving a car = secondary consciousness

Thinking about the meaning of life = more in the wheelhouse of primary consciousness (but don’t discount the mix of both!)

Most importantly, “the relationship between normal waking consciousness and ‘primary consciousness’ is not perfectly continuous”.

Cognition spectrum

The seeming ‘expansion of mind’ and ‘collapse of ego’ can be reconciled with observations of decreasing rather than increasing measures of brain activity. This can be done by proposing a model characterizing primary consciousness and secondary consciousness integrating into an…”us”. It is the crux underlying the hypothesis put forth by the paper:

A distinction is being made between two fundamentally different styles of cognition, one that is associated with the consciousness of mature adult humans, and another that is a mode of thinking the mind regresses to under certain conditions, e.g., in response to severe stress, psychedelic drugs and in REM sleep. The style of cognition that is dominant in normal waking consciousness will henceforth be referred to as secondary consciousness and the (pre-ego) style of cognition that is associated with primitive states will be referred to as primary consciousness

So how did Nutt and Carhart-Harris start testing the effects of psychedelics on human consciousness? In a placebo-control design, they put people in an fMRI scanner to observe changes in CBF (cerebral blood flow) using a technique called ASL (arterial spin labelling). Strikingly, “results revealed decreased CBF after psilocybin and no increases. The decreases were localized to high-level association cortices, including key regions of the DMN […]”. Using another kind of measure, BOLD (blood-oxygen level dependent) they repeated the measurements and found signals consistent with CBF measurements just obtained.

So magic mushrooms don’t over activate certain areas, on the contrary, they seem to quiet them!

They confirmed these patterns using 2 other measures: functional connectivity (FC) between different networks and oscillatory power between different brain regions. FC and oscillatory power also decreased. They are careful to note that there was no direct measure of entropy, per se. What can be said with more confidence is that there was disorganizing of brain activity. Doesn’t that make you think of the artists’ butterfly mind, moved by whatever breeze comes along? And why do we care if the DMN has decreased activity? Because it is “relatively removed from sensory processing and is instead engaged during higher-level, metacognitive operations such as self-reflection, theory-of-mind and mental time-travel” (aka trippy stuff). Decreased activity of the DMN putatively reflects lesser ‘constraint’ (not lesser ‘ability’ overall).

They also found that the DMN and TPN (task-positive networks) had a reduced ‘anticorrelation’. All this means is that the DMN and the TPN become less dissimilar, there was higher entropy (they’re less organized and thus more similar). The analogy is the more untidy rooms get, the more they will tend to resemble each other. When you clean-up a room it is organized in such a way that if you moved things around just a bit, you would notice it. Not so much in very untidy rooms.

This “inverse coupling” between the DMN and TPN is characteristic during ‘dual awareness’ meditation which collapses the sense of duality we hold. This is the spiritual experience as can best be inferred currently. Where “you” and “the world” both start and end is not clearly distinct anymore. Hence the sense of “oneness”. This fits closely with anecdotal accounts and provides a mechanistic starting point for these subjective experiences. This is great science tip-toeing towards an expanse of knowledge usually regarded as outside its realm of investigation. It is not. This is prejudiced thinking. Nothing in principle excludes a scientific approach to understanding consciousness.

In the words of the authors:

mainstream psychology and psychiatry have underappreciated the depth of the human mind by neglecting schools of thought that posit the existence [of] an unconscious mind. Indeed, psychedelics’ greatest value may be as a remedy for ignorance of the unconscious mind

This developing theory of consciousness proposed by Nutt and Carhart-Harris reveals how the prediction of increased brain activity on a psychedelic, as a general pattern, is incorrect. Quite the opposite is observed. Primary and secondary consciousness have been redefined for the exploratory purposes of the paper and they benchmark 2 states the brain transitions between as part of the psychedelic experience. This is a continuum, not a binary situation. It also explores how the dynamics of coupling between different networks change as to become more similar, maybe explaining part of the ego dissolution phenomenon, the sense of “oneness”.


Again, this paper should be read in its entirety because it contains so much more than what I described. I did not do it justice.

Let me know about your experiences with psychedelics. Do you have a better theory for consciousness? Do you challenge the methodology in the paper? What does you astrologer think of all this?


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