Consuming psychedelics and maintaining a meditation practice have both been known to have a beneficial effect on the mind, both emotionally and cognitively. Yet the research on how these therapeutic effects manifest in the brain is only emerging. In this post, we will focus on the shared neural process that underlie the effect known as “Ego Dissolution” which is believed to be involved in the positive impact of both psychedelics and non-dual meditation.
This is the experience described by people who have tried psychedelics in sentences such as “I cast off my ego”, “I felt liberated from the recurring worries that bother me”, “I felt a connection to others and to nature” or “I felt like my existence is timeless and my existential anxiety melted away.”
It’s impossible to speak about ego dissolution without noting that more than a few doctoral dissertations in philosophy and psychology have been written on the source of the sense of self, and of course, I have no way to present this topic here with the complexity it merits. I’ll suffice by saying that out of all the existing definitions of the sense of self, I think the simplest version that captures the phenomenological self requires only the ability to position the self in time and space.
This definition sounds complicated but actually, every film that engages in some way with a figure who finds her/himself in a different body characterizes the self in exactly this way. The servant who transforms into a teapot in “Beauty and the Beast,” the baby who speaks in “Look Who’s Talking,” girls who wake up in the body of a 30-year-old woman, adults who wake up as children, living people who turn into ghosts – all of these are different examples of defining the self according to the brain’s ability to identify its place on the timeline and in physical space. This definition is comprehensible to us, the observers, in a completely intuitive way.
This sense of self is based, to a large extent, on the combination of visual, bodily and vestibular (related to spatial orientation) data. This combination of sensory information from the external world and information from within the body, together with the brain’s own predictions, is in line with the Bayesian model of the brain. This is also called the minimal/body self-model.
According to the Bayesian model, the brain is a machine whose purpose is to test hypotheses. This mechanism produces an internal model of sensory data sources that are found in the world, but are inaccessible to it in an unmediated manner. This internal model becomes more sophisticated the more it tries to prevent surprises; it does this with the help of a combination of perception and action that leads to a reduction in the number of prediction errors.
According to this theory, if the brain predicts the sensory data sources in the external world, it can be assumed that it also foresees the contributing source of the organism itself to this sensory input. As such, the Bayesian model of the world should also include a self-model along the same minimal/body lines I described earlier, since this is the most logical explanation, statistically speaking, for the existence of identical sensory-motor stimuli.
So, how do psychedelic substances affect this process? The molecules of the classic psychedelics (such as LSD and psilocybin) appear to be connected to the weakening of the ability to hunt for our perceptual infrastructure with accurate predictions, based on data emerging from within the connection or on data based on previous predictions. The result? A reduction in perceptual processing, for better and for worse.
For worse, because in certain aspects, this perceptual processing is less reliable and is therefore accompanied by a feeling of uncertainly about what the senses are perceiving. For better, because at the same time, there is an improvement in those actions in which overactivity of our predictive machinery harms performance.
Research subjects who took LSD were less sensitive to the Hollow-Face Illusion (an optical illusion in which the brain perceives a concave mask of a human face as a normal convex face), while those under the influence of ayahuasca and psilocybin were more successful at tasks that required the reduction of binocular rivalry (a phenomenon of visual perception in which perception alternates between different images presented to each eye).
Of course, these findings are also linked to the way in which people under the influence of psychedelics experience routine occurrences as new and exciting, and mainly to the fact that people often label as “truth” the insights they gain while using psychedelics.
The fact that these experiences occur under the auspices of a partial pause of the indefatigable prediction mechanism contributes part of the explanation behind this labeling. These experiences are labeled as truth because they are based on an encounter with the sensory information coming from reality in a way that’s less limited by the brain’s predictions based on past events. In this sense, these experiences are more immediate. In other words, psychedelic experiences are labeled as truer also because, to a certain extent, they are indeed more true.
If we go back now to the thinking model that predicts the existence of the minimal/body self, we can assume that experiences of ego dissolution are linked to the psychedelic gum that’s stuck in the motor of the prediction machine, making it difficult to produce a sense of self. This sense commonly creates the ability to orient the self in space and set a boundary between the self and the world.
Now, as promised, a few words about the similarity of the party that takes place in the brain under the influence of psychedelics and the one that occurs under the influence of meditation. The feeling of oneness is one of the foundations of the meditation experience. Its creation is based, at least partially, on the reduction of brain processes involved with the establishment of a sense of self or those that contribute to it.
Today there are significant testimonies that regions of the brain such as the nodes in the area called the DMN (Default Mode Network) are involved in the processing related to the self and the preservation of the sense of self existing in space and time. Research that included brain imaging using various technologies has shown decreased activity in these areas both after ingesting classic hallucinatory substances and during meditation.
One of the accepted research hypotheses among psychedelic researchers today is that both during meditation and after taking psychedelics, activity in the DMN declines and the communication between the nodes there and other destinations in the brain membrane related to sensory and associative processing undergoes fundamental changes. These changes support the decreased importance attributed to the prediction of the existence of the self during mystical experiences. These changes are also in line with the feeling of the absence of a time-and-space framework that characterizes mystical experience.
More specifically, the amplitude of spontaneous fluctuations in the DMN decreases both during mindfulness meditation and after ingesting hallucinatory substances. Other findings along the same lines point to a reduction or pause in brain activity in additional areas during focused awareness meditation and open monitoring meditation.
For example, in regular brain activity, there’s a converse linkage between activity in the DMN (the region associated with focusing attention inward) and activity in the task-positive network (the region associated with directing attention outward). This converse linkage is significantly weakened under the influence of hallucinatory substances and during the practice of nondual meditation, and it’s likely that this is part of the infrastructure of the mystical experience attained during this type of practice.
These changes in brain activity are what we would expect to see when someone reports an experience of oneness, in which representations of internal mental objects merge with representations of external objects in the form that characterizes mystical experiences.