Beyond the Ego: Psychedelics and the Default Mode Network

In the world of psychedelic culture, few phrases are as common as “ego death”. Often described as the pinnacle of the psychedelic experience. Ego death (or ego dissolution) is a state in which the sense of self dissolves. This can, on the one hand, bring about a sense of pure connection and synergy with the world as a whole. On the other hand, if you are not prepared, it can be terrifying. The subjective experience of ego dissolution is now a formal aspect of psychological enquiry. We have developed tools to measure these experiences, such as the Ego Dissolution Inventory. In the 21st century, this phenomenon has been linked to a disruption in what is known as the Default Mode Network (DMN).

The term was first coined by a research group led by American neurologist Marcus Raichle, and it has slowly become a central part of the discourse around psychedelics. It is now cited in numerous articles and studies as the “seat of the ego”, the biological substrate of the self. That is to say, the DMN is your perception of YOU. Psychedelics have the ability to completely dismantle this. This link between DMN and the experience of ego death is one of the most significant breakthroughs in modern neuroscience. The DMN provides a concrete, observable position of and explanation for the mystery of human consciousness.

However, as is often the case, with its arrival into the mainstream, the scientific nuance underpinning our current understanding of the DMN is often lost or watered down. Casting the DMN as an antagonist in the narrative of a psychedelic experience is shortsighted. The opinion that the rigid “ego” which the DMN represents must be “turned off” to experience the true enlightenment psychedelics can provide is just plainly incorrect, and misses the point. This simplification is not only wholly inaccurate, but it in fact masks the true complexity of the interactions between psychedelics and the brain. 

As ever, the facts are more enlightening than simple myths. So, while we can very simply consider the DMN as the ego, thinking of it as a single, central point is unhelpful. Psychedelics do not just flip a switch off and on. The relationship between these substances and the DMN is nuanced. Think of it as less of an on/off relationship and more a variety of disorganising processes – the disintegration of usual connections, re-routing and temporary reorganising of the network of communication between different parts of the brain.

The discovery of the default mode network has fundamentally transformed our understanding of human brain function. A healthy, functioning DMN is essential for our day-to-day lives. Measuring the effects of psychedelics on it can provide us with great insight into its constituents and how they all work together. If we can avoid oversimplification and maintain a nuanced, scientifically grounded perspective, we can gain an in-depth understanding of what exactly happens to the brain during a psychedelic experience.

The DMN is a collection of different and interconnected regions of the brain. When an individual is focused on external stimuli (sight, sound, etc.), the DMN is typically suppressed. If an individual is not focused on external things, or in the absence of external stimuli completely the DMN switches or “defaults” to internally focused thinking (self-reflection, daydreaming, etc.) It is also hypothesised that the DMN is active during periods of rest. This allows us to reflect on our experiences, feelings, and social interactions, processing them and integrating them into our consciousness.

The DMN, so far as we are currently aware, encompasses several specific areas of the brain:

Medial Prefrontal Cortex (mPFC)

This region helps you to think about yourself, make decisions, and draw assumptions about what others are thinking.

The Posterior Cingulate Cortex (PCC)

When your mind wanders, this region helps you to remember personal memories and focus on your feelings.

The Precuneus

This area helps to create mental images, recall past events and maintain your sense of a singular self.

Angular Gyrus

This part of the brain assists with reading comprehension, mathematics, and spatial awareness (knowing where things are around you).

Since its discovery 20 years ago, the DMN has become a central area of research in the study of human cognition. Understanding how various parts of the brain connect and interact is key to assessing how our conscious experience is created. Understanding how these specific areas work will also allow us to explain why particular impairments may lead to psychological difficulties for an individual.

In the context of psychedelic usage, the area most appropriate for discussion of the DMN is surely its integral role in the sense of self, and what is known as “theory of mind”. As we can see above, both of these aspects of conscious experience involve multiple different areas of the brain to function normally. They are crucial, foundational elements of social interaction.

A healthy and functional DMN provides us with a stable sense of self and allows us to navigate a complex external world, which is just as interconnected and interrelated as the physiology of the mind internally. An unhealthy DMN can be the root cause of a myriad of mental health issues. A hyperactive, rigid DMN is a key indicator of conditions like depression and anxiety, causing excessive rumination on past perceived failures or incessant worrying about potential future scenarios. It is also posited that faults in the default network can cause uncontrolled mind-wandering in some forms of ADHD. In these situations, the DMN becomes somewhat akin to a cage for consciousness, where the individual is locked into particularly unhealthy modes of thinking, or negatively/incorrectly interpreting the world around them.

This is where psychedelics can play an important role. The rationale for psychedelic-assisted therapy has long been attributed to their ability to promote neuroplasticity (the brain’s ability to change). The structure of the DMN provides a clear explanation as to how and why psychedelics have the effect they do, and shows how they can be incredibly powerful therapeutic tools. 

The hypothesis that psychedelics have the ability to alter and disrupt the normal function of the DMN was confirmed in a series of landmark studies in the early 2010s. Robin Carhart-Harris, along with investigators at Imperial College London, used fMRI (functional magnetic resonance imaging) to monitor changes in the brain associated with blood flow when individuals were dosed with psilocybin (the active ingredient in magic mushrooms).

They observed a significant decrease in blood flow and, therefore, associated connectivity within the key regions of the brain that make up the DMN. These effects were mostly centred on the mPFC and the PCC – both areas with powerful associations to sense of self and sense of others. Simply put, psilocybin disorganised the mind. The normal inner narrator was quieted. A follow-up study of LSD in 2016, also carried out by Carhart-Harris and others at Imperial College London, confirmed these results, which allows us to further extrapolate psilocybin’s DMN-altering effects to psychedelics as a whole.

To explain the findings, Carhart-Harris proposed what he calls the “Entropic Brain” hypothesis. This theory uses the concept of entropy (level of organisation) from physics to describe the normal state of the brain as one of low entropy, and therefore highly ordered and constrained. The DMN operates as somewhat of a conductor for proceedings, keeping everything in balance so it all works efficiently. Psychedelics disrupt this control. Their interaction with serotonin receptors doesn’t just quiet the DMN, it splits it off almost entirely from areas of the brain which it usually regulates. This throws the brain into a state of much higher entropy, meaning it is more chaotic, less constrained and drastically more flexible. Long-established patterns of communication disintegrate, and new, novel connections are able to form.

In a lot of interpretations, the effects of the DMN are misattributed to simply turning it off or shutting it down completely. This is only partially true. While connectivity within the DMN itself decreases, concurrently, the connectivity between the DMN and other specialised areas of the brain, usually divorced entirely from the DMN, actually increases. Suddenly, these networks of the brain, which usually operate individually, begin communicating. This is the neurological explanation for what is known as synaesthesia (hearing colours, seeing sounds, etc.). It also explains the powerful emotions which we can attach to moments, memories, or simple objects and sounds when under the influence of psychedelics. This sense of significance and meaning is a direct result of the areas of our brain responsible for our experience of “meaning” interacting with areas which normally lack emotional responses.

At the extreme end of these effects, when a sufficiently high dose of psychedelics is taken, is the experience of ego death, or dissolution. As the DMN’s grip on the narrative of ourselves and our world loosens, this sense of separation and individuality begins to dissipate. The brain’s usual models of what makes objects, objects, or external and internal different to one another, are no longer there. So, rather than psychedelics being a simple off switch for the conductor of our mind, they perform more of a radical reorganisation. The disintegration of the DMN removes the barriers segregating brain processes, bringing about a state of intense interconnectedness.

As a result of these wide-ranging effects, there are a lot of misconceptions which are worth breaking down further. Let’s move away from neurobiology so we can get some more clarity as to how these effects are actually experienced.

The “Off Switch”

The most common myth, as we discussed above, is that psychedelics literally just “turn off” the DMN, completely shutting down the ego like it’s an on/off switch. This is inaccurate. It may be helpful to think of consciousness as a whole as, perhaps, an orchestra. The DMN acts as a conductor, ensuring all elements of the orchestra remain coherent. A psychedelic does not just stop the music playing. Instead, the conductor leaves the stage and the musicians, now lacking top-down control, begin to improvise and form new, unexpected melodies among themselves. While this is undoubtedly more chaotic and less narratively coherent, it could create something more novel, creative and unexpected. So, the components making up the DMN are all, in fact, still active. It is merely the lack of an organiser, rather than a cessation of activity.

The DMN is Bad

Because, as we have seen, an overactive DMN can be linked to issues such as depression and anxiety, it is easy to frame it as something to be conquered. A villain, controlling and restricting. This is an extremely dangerous misunderstanding. A healthy, normally functioning DMN is essential to a stable life. Without it, you would have an inconsistent identity, narratively incoherent memories, or any ability to plan for the future. If you take this in a moment-to-moment sense, this could literally amount to an inability to feed yourself or differentiate yourself from another individual.

The therapeutic potential of psychedelics does not seek to remove or eliminate the influence of the DMN, but simply to disrupt its rigidity. For someone trapped in a spiral of depression, for example, the DMN has become fixed in an unhealthy loop. A psychedelic acts as a “reset”, temporarily and often forcefully removing the DMN from this destructive pattern, and allowing new connections to form. The aim is to increase psychological flexibility in an individual, not completely and permanently silence their sense of self.

Psychedelics are the Only Way

A final, too common belief is that psychedelics are the only means with which we can quiet the DMN. This is completely untrue. While psychedelics are an incredibly powerful tool to chemically induce a state of temporary change, other practices can be just as effective (albeit through more concerted, long-term effort). In a 2011 study, Judson Brewer discussed the potential of meditation to alter DMN connectivity. Results indicated that experienced meditators exhibit significantly reduced DMN activity both while meditating and at baseline. Through thousands of hours of practice, they have manipulated their brains so they are less caught up in self-referential thinking.

There are similar findings of the popular “flow state” described by Mihaly Csikszentmihalyi, which describes the ability of an artist, athlete, musician, etc., to become fully absorbed in their craft. Csikszentmihalyi reported that during the flow state, there was a significant decrease in activity associated with the DMN. So, while psychedelics can provide perhaps a shortcut to this mental state, these effects are far from unique.

The Default Mode Network is not the enemy, or something to overcome, where psychedelics are concerned. Neither is it the single source of the “ego”. It is a fundamental network of interconnected regions of the brain responsible for our perception, inner and outer. The groundbreaking aspect of psychedelic research associated with this is the discovery that we can actively manipulate the DMN to better ourselves. The power here is not in shutting anything off; it is in altering pathways and providing more flexibility for new and novel connections to be made.

Understanding the nuances of this process is essential. Moving past short-sighted myths like the “off switch” allows us to make use of the DMN rather than trying to squash it. The therapeutic goal is not the ego death/dissolution itself, but the promotion of renewed psychological flexibility.

If these substances are ever going to receive full clinical approval, we need to fully understand their impacts. There is immense therapeutic potential here, but only if we accept that the goal is never annihilation but reorganisation. The temporary disintegration of rigid thought patterns and patterns of behaviour can provide a window of opportunity for us to re-evaluate why we are stuck in these patterns, alter our ingrained biases, escape our loops, and begin to establish healthier patterns for the future.

David is one of our community bloggers here at Chemical Collective. If you’re interested in joining our blogging team and getting paid to write about subjects you’re passionate about, please reach out to Sam via email at [email protected]