The New Science of Psychedelics

By Michael Pollan

“The impact of these two molecules (LSD and psilocybin) is hard to overestimate. The advent of LSD can be linked to the revolution in brain science that begins in the 1950s, when scientists discovered the role of neurotransmitters in the brain. That quantities of LSD measured in micrograms could produce symptoms resembling psychosis inspired brain scientists to search for the neurochemical basis of mental disorders. At the same time, psychedelics found their way into psychotherapy, where they were used to treat a variety of disorders, including alcoholism, anxiety and depression. For most of the 1950s and early 1960s, many in the psychiatric establishment regarded LSD and psilocybin as miracle drugs.”

“The arrival of these two compounds is also linked to the rise of the counterculture during the 160s…For the first time in history, the young had a rite of passage all their own: the ‘acid trip’…Yet by the end of the 1960s, the social and political shock waves unleashed by these molecules seemed to dissipate. The dark side of psychedelics began to receive tremendous amounts of publicity…As quickly as the culture and scientific establishment had embraced psychedelics, they now turned sharply against them…Then something unexpected and telling happened. Beginning in the 1990s, well out of the view of most of us, a small group of scientists, psychotherapists and so called psychonauts, believing that something precious had been lost from both science and culture, resolved to recover it.”

Accepted in 2006, this paper published by a team at John Hopkins was a thirty volunteer double blind study looking at the effect of psilocybin under controlled conditions. Prior to 1965, there had been more than a thousand scientific papers on psychedelic drug therapies involving more than 40,000 volunteers.

“Thirty volunteers who had never before used psilocybin had been given a pill containing either a synthetic version of psilocybin or an “active placebo” to fool them into thinking they had received the psychedelic. They then lay down on a couch wearing eyeshades and listening to music through headphones attended the whole time by two therapists. After about thirty minutes, extraordinary things began to happen in the mids of the people who had gotten the psilocybin pill.

The study demonstrated that a high dose of psilocybin could be use to safely and reliably “occasion” a mystical experience — typically described as a dissolution of one’s ego followed by a sense of merging with nature or the universe….

What was most remarkable about the results reported in the article is that participants ranked their psilocybin experience as one of the most meaningful in their lives, comparable to the birth of a first child or death of a parent. Two-thirds of the participants rated the session among the top 5 most spiritually significant experiences of their lives”

“As a young chemist working in a unit of Sandoz Laboratories charged with isolating the compounds in medicinal plants to find new drugs, Hofmann had been tasked with synthesising, one by one, the molecules in the alkaloids produced by ergot. Ergot is a fungus that can infect grain, often rye, occasionally causing those who consume bread made from it to appear mad or possessed. But midwives had long used ergot to induce labour and stanch bleeding postpartum, so Sandoz was hoping to isolate a marketable drug from the fungus’s alkaloids. In the fall of 1938, Hofmann made the twenty-fifth molecule in this seres, naming its lysergic acid diethyl-amide r LSD — 25 for short. Preliminary testing of the compound on animals did not show much promise (they became restless, but that was about it), so the formula for LSD-25 was put on the shelf.

And there it remained for five years, until one April day in 1943, in the middle of the war, when Hofmann had a “peculiar presentiment” that LSD-25 deserved a second look….An other mysterious anomaly occurred when he synthesised LSD-25 for the second time. Despite the meticulous precautions he always took when working with a substance as toxic as ergot, Hofmann must somehow have absorbed a bit of the chemical through his skin because he was “interrupted in my work by an unusual sensation”. Hoffman went home, lay down on a couch, and “in a dreamlike state, with eyes closed..I perceived an uninterrupted stream of fantastic pictures, extraordinary shapes with intense, kaleidoscopic play of colours.”

“Many experiments had been performed in the early 1960s related to how psilocybin can lead to spiritual growth “The mot famous of these was the Good Friday or Marsh Chapel Experiement conducted in 1962 by Walter Pahnke, a psychiatrist and minister working on a PhD dissertation at Harvard under Timothy Leary. In this double-blind experiment, twenty divinity students received a capsule of white powder during a Good Friday service at Marsh Chapel on the Boston University campus, ten of them containing psilocybin, ten an active placebo…Eight of the ten students receiving psilocybin reported a powerful mystical experience, while only one in the control group did. Pahnke concluded that the experiences of those who receive psilocybin were indistinguishable from, if not identical with the classic mystical experiences reported in literature.”

What is really important for you to understand,” he said, “is that there was a sudden doubling of the human brain 200,000 years ago. From an evolutionary point of view, that’s an extraordinary expansion. And there is no explanation for this sudden increase in the human brain.” — Stamets “Psilocybin Mushrooms and the Mycology of Consciousness” at Psychedelic Science 2017

“Psyilocybes gave our hominid ancestors “access to realms of supernatural powers,” “catalysed the emergence of human self-reflection” and “brought us out of the animal mind and into the world of articulated speech and imagination”.

In his book Food of the Gods, McKenna proposed that the transformation from humans’ early ancestors Homo erectus to the species Homo sapiens mainly had to do with the addition of the mushroom Psilocybe cubensis in its diet, an event that according to his theory took place in about 100,000 BCE (which is when he believed that the species diverged from the genus Homo).McKenna based his theory on the main effects, or alleged effects, produced by the mushroom while citing studies by Roland Fischer et al. from the late 1960s to early 1970s.

McKenna stated that due to the desertification of the African continent at that time, human forerunners were forced from the increasingly shrinking tropical canopy in search of new food sources.He believed they would have been following large herds of wild cattle whose dung harbored the insects that, he proposed, were undoubtedly part of their new diet, and would have spotted and started eating Psilocybe cubensis, a dung-loving mushroom often found growing out of cowpats.

McKenna’s hypothesis was that low doses of psilocybin improve visual acuity, particularly edge detection, meaning that the presence of psilocybin in the diet of early pack hunting primates caused the individuals who were consuming psilocybin mushrooms to be better hunters than those who were not, resulting in an increased food supply and in turn a higher rate of reproductive success.Then at slightly higher doses, he contended, the mushroom acts to sexually arouse, leading to a higher level of attention, more energy in the organism, and potential erection in the males, rendering it even more evolutionarily beneficial, as it would result in more offspring.At even higher doses, McKenna proposed that the mushroom would have acted to “dissolve boundaries,” promoting community bonding and group sexual activities.Consequently, there would be a mixing of genes, greater genetic diversity, and a communal sense of responsibility for the group offspring.At these higher doses, McKenna also argued that psilocybin would be triggering activity in the “language-forming region of the brain”, manifesting as music and visions, thus catalyzing the emergence of language in early hominids by expanding “their arboreally evolved repertoire of troop signals.”He also pointed out that psilocybin would dissolve the ego and “religious concerns would be at the forefront of the tribe’s consciousness, simply because of the power and strangeness of the experience itself.”

“The brain is a hierarchical system” Carhart-Harris explained in one of our interviews. “The highest-level parts “ — those developed late in our evolution, typically located in the cortex — “exert an inhibitory influence on the lower-level parters, like emotion and memory.” As a whole, the default mode network exerts a top-down influence on other parts of the brain, many of which communicate with one another through its centrally located hub. Robin has described the DMN variously as the brain’s “orchestra conductor” or “capital city” charged with managing and “holding the system together”.

The brain consist of several different specialised systems-one for visual processing, for example, another to control motor activity-each doing its own thing. “Chaos is averted because all systems are not created equal,” Marcus Raichle has written…The default mode network keeps order in a system so complex it might otherwise descend into the anarchy of mental illness. As mentioned the DMN appears to play a role in the creation of mental constructs or projections, the most important of which is the construct we call the self or ego.

…The achievement of an individual self, a being with a unique past and a trajectory into the future, is one of the glories of human evolution, but it is not without its drawbacks and potential disorders. The price of the sense of an individual identity is a sense of separation from others and nature….accepting the good with the bad, most of us take this self an an unshakable given, as real as anything we know, and as the foundation of our life as conscious human beings. Or at leat I always took it that way, until my psychedelic experiences led me to wonder.

Perhaps the most striking discovery of Carhart-Harris’s first experiment was that the steepest drops in DMN activity correlated with his volunteer’s subjective experiences of “ego dissolution”…Shortly after Carhart-Harris published his results in a 2012 paper in PNAS, Judson Brewer a researcher at Yale who was using fMRI to study the brains of experienced meditators, noticed that his scans and Robin’s looked remarkably alike. The transcendence of self report by expert mediators showed up on fMRIs as a quieting of the DMN…This sense of merging into some larger totality is of course one of the hallmarks of the mystical experience; our sense of individuality and separateness hinges on a bounded self and a clear demarcation between subject and object. But all of that may be a mental construction, a kind of illusion.”

… By quieting the default mode network, these compounds can loosen the ego’s grip on the machinery of the mind, “lubricating” cognition where before it had been rusted stuck. Psychedelics alter consciousness by disorganising human activity” Carhart Writes. They increase the amount of entropy in the brain, with the result that the system reverts to a less constrained mode of cognition. “It’s not just that one system drops away” he says “but that an older system emerges.” That older system is primary consciousness, a mode of thinking in which the ego temporarily loses its dominion and the unconscious, now unregulated, “is brought into an observable space.”

When the memory and emotion centers are allowed to communicate directly with the visual processing centers, it’s possible our wishes and fears, prejudices and emotions begin to inform what we see — a hallmark of primary consciousness and a recipe for marginal thinking. Likewise, the establishment of new linkages across brain systems can give rise to synetshesia, as when sense information gets cross wired so that colours become sounds or sounds become tactile. Or the new links give rise to hallucinations, as when the content of my memory transformed my visual perception of Mary into Maria Sabina, or the image of my face in the mirror into a vision of my grandfather.

“So what does a high-entropy brain look like? The various scanning technologies that the Imperial lab has used to map the tripping brain show that the specialised neural networks of the brain — such as the default mode network and the visual processing system — each become disintegrated, while the brain as a whole becomes more integrated as new connections spring up among regions that ordinarily kept mainly to themselves or were linked only via the central hub of the DMB. The various networks of the brain became less specialised.”

“When the brain operates under the influence of psilocybin, as shown on the right, thousands of new connections form, linking far flung brain regions that during normal waking consciousness don’t exchange much information”

“In the Philosophical Baby, Gopnik draws a useful distinction between the “spotlight consciousness” of adults and the “lantern consciousness” of young children. The first mode gives adults the ability to narrowly focus attention on a goal (In his own remarks,, Carhart-Harris called this “ego consciousness” or “consciousness with a point.”) In the second mode — lantern consciousness —attention is more widely diffused, allowing the child to take information from virtually anywhere in her field of awareness, which is wide, wider than most adults….The adult brain directs the spotlight of its attention where it will and then relies on predictive coding to make sense of what is perceives. This is not at all the child’s approach, Gopnik has discovered. Being inexperienced in the way of the world, the mind of the young child has comparatively few priors, or preconceptions, to guide her perceptions down the predictable tacks. Instead, the child approaches reality with the astonishment of an adult on psychedelics.

What this means for cognitin and learning can be best understood by looking at machine learning, or AI, Gopnik suggets. In teaching computers how to learn and solve problems, AI designers speak in terms of “high temperature” and “low temperature” searchs for the answers to questions. A “low temperature” search (so called because it requires less energy) involves reaching for the most probable or nearest-to-hand answer, like the ones that worked for similar problems in the past. Low-temperature search requires more energy because it involves reaching for less likely but possibly more ingenious and creative answers — those found outside the box of preconception. Drawing on its wealth of experience, the adult mind performs low-temperature searches most of the time. Gopnik believes that both young children and the adult on a psychedelia have a strong predilection for the temperature search; in their quest to make sense of thing, their minds explore not just the nearby and most likely but the entire space of possibilities. These high-temperature searches might be inefficient, incurring a high rate of error and requiring more time and mental energy to perform. High-temperature searches can yield answers that are more magical than realistic. Yet there are times when hot searches are the only way to solve a problem, and occasionally they return answers of surpassing beauty and originality. E=mc2 was the product of a high-temperature search.