Mushrooms, Meditation, and Flow

During the last five years, I have done almost nothing but study the brain. When I finished my Bachelor of Science at the University of Victoria, I felt I had a thorough grasp of neurobiology and neuropsychology. But a week after graduating, I came across a paper from Imperial College London called “The entropic brain: A theory of conscious states informed by neuroimaging research with psychedelic drugs” which proposed no less than a radical new model of the physical substrates underlying consciousness and mental illness. This unique, engrossing paper exposed gaping holes in my understanding of the brain, and revealed just how much I have yet to learn. The thread of fascinating, important research it illuminated has obsessed me ever since, and is the focus of this essay.

This story begins in 2001 at the Washington University School of Medicine, when a neuroscientist named Marcus Raikle was collecting baseline scans for his Functional Magnetic Resonance Imaging (fMRI) experiments. fMRI localizes neural activity in real time. It harnesses the different magnetic properties of oxygenated and deoxygenated hemoglobin (the protein which houses oxygen in blood) to track cerebral blood flow as a proxy for “activity.” fMRI facilitates precise detection of which brain areas are active while people perform various tasks. Raikle – like any good scientist – was collecting control readings as a basis for comparison. To do this, he would tell subjects to lie in the scanner and do nothing. When analyzing these scans, he came across something counterintuitive. Far from being dormant, when people “do nothing,” their brains exhibit a consistent pattern of activity. When “doing nothing,” a network of brain areas in the frontal and temporal lobes were in constant communication. Raikle called this system the default mode network (DMN)1. The main nodes in the DMN are the posterior cingulate cortex, the medial prefrontal cortex, the angular gyrus, and the hippocampus. On its face, Raikle’s discovery seems inconsequential. But to understand the profound implications of this neural network, we need to drill down and examine precisely what it does.

The nodes which comprise the default mode network are literally what make us human. They distinguish our neurological functioning from that of other animals. The DMN comes online in three all too familiar, distinctively human scenarios: rumination, anticipation, and self-referential processing. When your mind wanders to the time in freshman year when some prick cut you off in the cafeteria line, your DMN is active. When you feel a pang of anxiety about going to a big social event, your DMN is active. When you’re scrolling through instagram comparing yourself to the flawless personas that people present online – feeling a good dose of jealousy and resentment about your relative status in the social hierarchy – your DMN is active. It’s the seat of the Freudian ego, the system which metaphorically houses the “self.” The DMN is not exclusively negative, though. It facilitates sophistication. Rumination lets us extract meaning from the past. Anticipation lets us simulate potential plans of actions in our prefrontal cortex, so our simulations can die instead of us. Self referential processing lets us learn how everything we observe relates to us, so we can learn from the mistakes of others rather than commit them ourselves. These abilities are philosophically interesting in their own right. But as scientists further studied the function of these double edged, uniquely human capacities, it began to appear as if the DMN might hold a fundamental key to understanding topics which extend beyond the merely philosophical.

The professionals who are tasked with formulating the DSM, the manual which catalogues mental disorders, face the technical problem of delineating borders. It’s difficult to categorize things – to know where one ends, and another begins. Is the correct level of analysis the behavioural, or the biochemical? How much overlap is needed for two phenomena to be seen as one? How much separation is needed to deem two disorders distinct? If two disorders share a common cause, but manifest in different ways, are we correct to draw a border between them? These questions, though difficult to answer, lead us nicely into our discussion of the DMN. The relevant literature implicates abnormal DMN activity in a host of seemingly disparate disorders. Researchers have shown, for example, that an overactive DMN predicts depression2. Other data indicate that DMN hyper-connectivity predicts social anxiety3. There is also research implicating hyperactive DMN functioning in addiction4. Let’s tease apart this conceptual link. Imagine having a hyperactive DMN. This would mean being stuck in the past or future, perpetually analyzing how everything in life relates to you. This would be a self-focussed life divorced from the present moment. Have you ever felt stuck in a mental rut? Trapped in a pernicious, predictable pattern of thoughts from which you can’t escape? Hot take: that’s what it feels like to have a DMN running on overdrive. To illustrate how a hyperactive DMN might form a common basis for a set of disorders, I’m going to borrow an analogy from Michael Pollan (whose book “How to Change your Mind” elaborates on this topic more eloquently and thoughtfully than I ever could). Imagine the brain as a ski-hill, with thoughts as grooves in the mountain. Grooves are built into the hill by thousands of runs down them. Once they are formed, you have no choice but to follow the beaten path. This is how it feels to be held hostage by a depressive, anxious, or addictive chain of thoughts. I would characterize these horrible afflictions – depression, anxiety, and addiction – as pathologies of hyper-order. They derive from seemingly inescapable, rigid thought patterns, which once initiated, propagate like a fixed sequence of dominos. If the brain is a ski-hill, and negative thought patterns are grooves on the mountain, an obvious question emerges: are there ways to shake the snow globe, to add fresh powder with which alternate grooves can be formed?

An eccentric, British, psychoanalytically-minded neuroscientist called Robin Carhart-Harris has spent much of his career answering this question. It may surprise you that his research has led him to explore the therapeutic potential not of pharmaceutical, but of psychedelic drugs. In particular, he has focussed on a compound called psilocybin, the psychoactive compound in magic mushrooms. His day job is to give people psilocybin, and scan their brains. His lab’s findings are as counterintuitive as they are groundbreaking. What do you think happens to people’s brains when they take psychedelics? I predicted that there would be erratic bursts of activity, all over the brain. I figured that these drugs would add something. I was half correct. When people take psilocybin, new connections are formed in areas which usually don’t communicate, which probably accounts for the unique phenomenology of the psychedelic experience 5. But I was only half correct. Carhart-Harris also found that in most routinely active networks, activity decreases. And it decreases most significantly in one area: the default mode network. When someone takes psilocybin, their DMN basically shuts off. Recent studies confirm that this pattern holds for Ayhuasca6 and LSD7. The result of this neural alteration manifests in a starkly unique experience for the user. Their sense of self erodes. Mental time travel halts; everything is now. The past ceases to matter, and the future vanishes. If the DMN constitutes the well beaten neurological path down the mountain, we’ve found our first way to shake the snow globe. Psychedelics alter perceptual machinery to such a degree that users are thrust out of their typical schema, and can view themselves and the world in an entirely new light. In a study which employed a single-dose of psilocybin as a treatment for nicotine addiction, multiple subjects reported what the lead investigator called a “duh” moment, an obvious epiphany. They remarked that while under the influence of this compound, they could view themselves and their habits in third person, which made them realize that inhaling tar into their delicate lungs wasn’t a good idea. To the degree that the default mode network entrances us in a self-focussed narrative, it seems likely that these “duh” moments derive from dialing it down a few notches. Critically, participants translated their powerful realizations into action; the study achieved a mind-boggling quit rate of 80% after 6 months, 55% better than the next best pharmaceutical treatment8. If you don’t find those numbers shocking, I would suggest rereading the previous sentence. Knowing the connection between a hyperactive DMN and depression, anxiety, and addiction, we can view some groundbreaking contemporary research with appropriate context. A fascinating study at John’s Hopkins9 recently examined the effects of medically supervised psilocybin trips on the death anxiety of terminally ill cancer patients (yes, you read that right). After a single dose, patients showed a staggering decrease in death anxiety, and remarkable improvements in their mental health more generally. Some of the testimonials are striking (for more, see: How to Change Your Mind). While there are obvious risks to casual psychedelic use, their potential to be used in a medical setting to treat certain pathologies of hyper-order is utterly fascinating, and if nothing else, warrants further study.

If you suffer from a pathology of hyper-order, but are trepidatious about entering the world of psychedelics, let’s examine a second way to shake the snow globe. In the last two decades, there have been thousands of papers published on the science of meditation. To me, this is where the story becomes applicable to most people’s lives. A few years ago, researchers set out to image the brains of experienced meditators, in an attempt to formulate a mechanistic account of why meditation so reliably improves well-being, and mitigates certain pathologies. They canvassed the world for monks willing to meditate in an fMRI tube (what a world we live in), and brought them to the lab to image their brains. What they discovered absolutely floored me. Just like the minds of those under the influence of psychedelics, the default mode network goes offline during meditation 10 11. As someone who has practiced meditation for 5 years, this makes sense. The meditative injunction is simply to observe the present. For brief portions of a meditation session – those from which I derive much of the value – I lose my sense of time, I step outside of the illusion of “self,” and I merely experience each moment for what it is, empirically. I stop appraising the character of experience, and observe it instead. I cease, if only for a few moments at a time, to be a “human doing” and merely exist as a human being. Meditation seems to mirror psychedelics in its effects on the brain and corresponding phenomenology, but the question remains: how does it stack up as a tool to treat mental illness, or increase well-being? As documented by the brilliant Jonathan Haidt in his first book, The Happiness Hypothesis12, there are three primary interventions which reliably improve well-being: Prozac, cognitive behavioural therapy, and meditation. If psychedelics are a metaphorical rocket ship which catapult you towards ego death and a novel perspective, meditation is a slow, steady train heading to the same destination.

To summarize: depression, anxiety, and addiction are characterized in part by default mode network hyperactivity. Psychedelics and meditation turn down the dial on the DMN. Both interventions are effective at treating what I call disorders of hyper-order. Lastly, I’d like to step outside the realm of science, and into the domain of conjecture, to discuss one last means by which it may be possible to shake the neurological snow globe: flow.

Few concepts have captured the interest of social psychologists in the last four decades more than “flow,” a term coined by Mihaly Csikszentmihalyi (what a name) in 197513. A flow state is one of total immersion. When you are lost in your work, a song, or a piece of art, you’ve found flow. Though I couldn’t find any research examining the link between the default mode network and flow (someone should do the experiment), I suspect that flow is another way to shut off the DMN. During flow, “time flies by” and you cease to think about what you’re doing. Flow gets you out of your head, so to speak. To me, this description screams of an inactive DMN. Flow can be cultivated strategically, by engaging in activities that are sufficiently challenging, but not overwhelming. To find flow is to walk the tight rope between boredom and anxiety. Flow is to be found where the Taoists advise us to find meaning: on the border between order and chaos. Pick an activity that excites and engages you, but doesn’t disorient and overwhelm you, and I would bet that you’re turning the dial back on the DMN, doing your mental health a lot of good in the process. Learn the piano, but don’t start with Vivaldi. Play a sport, but don’t be the best – or worst – player on the team. Never be the smartest person in the room. If you’re feeling bored, or overwhelmed, you’re in the wrong place, doing the wrong thing.

What should we take from this story? Should we spend our lives hellbent on deactivating our default mode networks, in hopes of achieving enlightenment, and staving off mental illness? Before jumping to that conclusion, let’s analyze the opposite pole of the order-chaos spectrum. An equally frightening state resides on the chaotic pole. A “bad trip” on psychedelics, for example – where the DMN is nowhere to be found – is in some ways indistinguishable from psychosis (which, by the way, might explain why individuals who are predisposed towards schizophrenia should not experiment with psychedelics). In such a state, perception is so flexible and reality is so distorted that there is no grounding narrative. There is no past, no future, and no self. Such a state, obviously, is sub-optimal for a human trying to function in the world. If depression, anxiety, and addiction can be conceptualized as pathologies of hyper-order, the hyper-chaotic states at the other end of the spectrum, if sustained over time, are equally damaging. As the pendulum swings between these poles, we would be wise to assume an orientation of balance, using the tools available to plant one foot in chaos, the other in order, adjusting as we see fit.

1. Raichle, M. E., MacLeod, A. M., Snyder, A. Z., Powers, W. J., Gusnard, D. A., & Shulman, G. L. (2001). A default mode of brain function. Proceedings of the National Academy of Sciences, 98(2), 676-682.

2. Sheline, Y. I., Barch, D. M., Price, J. L., Rundle, M. M., Vaishnavi, S. N., Snyder, A. Z., … & Raichle, M. E. (2009). The default mode network and self-referential processes in depression. Proceedings of the National Academy of Sciences, 106(6), 1942-1947.(1)

3. Maresh, E. L., Allen, J. P., & Coan, J. A. (2014). Increased default mode network activity in socially anxious individuals during reward processing. Biology of mood & anxiety disorders, 4(1), 7.

4. Ma, N., Liu, Y., Fu, X. M., Li, N., Wang, C. X., Zhang, H., … & Zhang, D. R. (2011). Abnormal brain default-mode network functional connectivity in drug addicts. PloS one, 6(1), e16560.

5. Roseman, L., Leech, R., Feilding, A., Nutt, D. J., & Carhart-Harris, R. L. (2014). The effects of psilocybin and MDMA on between-network resting state functional connectivity in healthy volunteers. Frontiers in human neuroscience, 8, 204.

6. Palhano-Fontes, F., Andrade, K. C., Tofoli, L. F., Santos, A. C., Crippa, J. A. S., Hallak, J. E., … & de Araujo, D. B. (2015). The psychedelic state induced by ayahuasca modulates the activity and connectivity of the default mode network. PloS one, 10(2), e0118143.

7. Carhart-Harris, R. L., Muthukumaraswamy, S., Roseman, L., Kaelen, M., Droog, W., Murphy, K., … & Leech, R. (2016). Neural correlates of the LSD experience revealed by multimodal neuroimaging. Proceedings of the National Academy of Sciences, 113(17), 4853-4858.

8. Johnson, M. W., Garcia-Romeu, A., Cosimano, M. P., & Griffiths, R. R. (2014). Pilot study of the 5-HT2AR agonist psilocybin in the treatment of tobacco addiction. Journal of psychopharmacology, 28(11), 983-992.

9. Griffiths, R. R., Johnson, M. W., Carducci, M. A., Umbricht, A., Richards, W. A., Richards, B. D., … & Klinedinst, M. A. (2016). Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial. Journal of psychopharmacology, 30(12), 1181-1197.

10. Brewer, J. A., Worhunsky, P. D., Gray, J. R., Tang, Y. Y., Weber, J., & Kober, H. (2011). Meditation experience is associated with differences in default mode network activity and connectivity. Proceedings of the National Academy of Sciences, 108(50), 20254-20259.

11. Berkovich-Ohana, A., Glicksohn, J., & Goldstein, A. (2012). Mindfulness-induced changes in gamma band activity–implications for the default mode network, self-reference and attention. Clinical Neurophysiology, 123(4), 700-710.

12. Haidt, J. (2006). The happiness hypothesis: Finding modern truth in ancient wisdom. Basic Books.

13. Csikszentmihalyi, M., & Csikszentmihalyi, I. (1975). Beyond boredom and anxiety (Vol. 721). San Francisco: Jossey-Bass.