New study sheds light on how DMT alters brain waves to induce the loss of self

A recent study published in The Journal of Neuroscience found that the psychedelic drug DMT pushes brain activity away from its usual balanced state and toward a more random, less structured pattern. This shift in brain dynamics directly corresponds to the intense feeling of losing one’s sense of self, an experience often reported during psychedelic trips. The results provide a new biological lens through which to view the way human consciousness is constructed and maintained.

To understand the research, it helps to look at a concept from physics called criticality. A system at criticality sits right on the boundary between complete order and total chaos. The human brain normally operates very close to this critical point. Remaining near this boundary allows brain regions to communicate efficiently across both short and long distances.

This state produces a rich variety of brain wave patterns that scientists consider essential for healthy mental function and conscious awareness. When the brain functions near criticality, its electrical activity exhibits what researchers call long-range temporal correlations. This means that past electrical activity in the brain continues to influence future activity over extended periods. Rather than fading out quickly, the echoes of past brain waves linger.

This long-lasting echo effect provides a form of short-term biological memory. It helps humans maintain a coherent stream of thought and a stable sense of identity over time. Classic psychedelics like DMT profoundly alter human perception and brain function by disrupting these normal rhythms. People who take high doses often report a complete breakdown of their normal identity, a phenomenon known as ego dissolution.

During this experience, the boundary between the internal self and the external world appears to vanish. Researchers wanted to know exactly how a powerful psychedelic changes the physical behavior of brain waves to produce this sensation. The research was conducted by a team of scientists including lead authors Mona Irrmischer and Marco Aqil, who are affiliated with the Academic Center for Trauma and Personality in the Netherlands and Imperial College London, respectively. They aimed to see if changes in brain criticality could explain the intense subjective effects of psychedelics.

The research team combined data from two separate studies involving a total of 27 healthy adult participants. In both experiments, participants received an intravenous dose of DMT on one day and a placebo of saline solution on a different day. The researchers recorded the electrical activity of the participants’ brains using electroencephalography, or EEG. This technique involves placing small sensors across the scalp to detect the electrical impulses produced by neurons.

The brain recordings were taken before the injection and continued for twenty minutes afterward. Once the drug’s effects wore off, participants filled out questionnaires rating their subjective experiences. The researchers specifically focused on a question asking participants to rate the statement, “I experienced a disintegration of my usual sense of ‘self’ or ‘ego.’”

To analyze the brain wave data, the team measured the presence of long-range temporal correlations. They used a mathematical tool called detrended fluctuation analysis. This analysis produces a numerical value indicating how close the brain is to a critical state. A value near one suggests a highly structured, complex system near criticality, similar to what scientists call pink noise.

A value near one half indicates a highly random, structureless system far from criticality, comparable to the static of white noise. The researchers found that DMT caused a widespread drop in these numerical values across multiple frequency bands of brain activity. Specifically, the drug shifted the theta, alpha, and beta brain waves away from their normal critical state. Alpha waves typically relate to wakeful relaxation, theta waves are involved in memory, and beta waves are associated with active thinking.

Under the influence of DMT, the brain signals in these frequencies became less complex and more random, resembling the static of white noise. The team then took their analysis a step further to determine the exact nature of this shift. They applied a newly developed mathematical metric that measures the ratio between excitatory and inhibitory brain activity. Brain networks rely on a delicate balance between neurons that stimulate activity and neurons that suppress it.

The coordination of these two forces dictates how information flows through the brain. This measurement helps scientists distinguish whether a brain has shifted into an overactive, supercritical state or an underactive, subcritical state. The results showed that DMT pushed alpha and beta brain waves into a subcritical regime. In this context, the brain networks shifted toward a state dominated by inhibitory signals.

This subcritical state features high randomness but low complexity. The brain’s electrical signals lose their intricate, long-lasting structure and become more uniformly chaotic. Finally, the researchers compared these physical brain measurements with the subjective ratings provided by the participants. They discovered a direct mathematical relationship between the drop in criticality and the intensity of the reported ego dissolution.

The further the alpha and theta brain waves shifted away from criticality, the more intensely the participants felt their sense of self disintegrate. The researchers noted that the shifts away from criticality seen with DMT share similarities with brain states observed during general anesthesia and deep meditation. While anesthesia involves a loss of consciousness and psychedelics involve intense emotional experiences, they both feature a breakdown of the normal, self-reflective stream of thought. This suggests that a subcritical shift in alpha brain waves might be a biological marker for the loss of the conscious self.

The findings add a new layer of detail to the entropic brain hypothesis, a popular theory suggesting that psychedelics increase the overall randomness of the brain. The new data align with the idea that randomness increases under DMT. Yet they provide a new perspective by showing that this randomness corresponds to a drop in mathematical complexity. Rather than moving toward a highly organized but hyperactive state, the brain waves simply lose their intricate architecture.

The specific definitions of complexity and randomness used in this physical analysis warrant precise distinction. In some scientific contexts, a higher degree of randomness implies that a system is more complex. However, in this mathematical framework, the subcritical state induced by DMT is less statistically complex than normal waking consciousness. The brain’s electrical patterns become less predictable, but they also lose the rich structural variety that defines normal cognition.

The study measured brain activity using EEG sensors on the scalp, which primarily capture slower brain waves. It remains possible that faster brain oscillations, which are harder to measure with scalp sensors, behave differently. These high-frequency waves might shift into an overactive, supercritical state under the influence of DMT. Such an overactive state might account for the vivid hallucinations and rich emotional content of the psychedelic trip.

Future research could explore how these high-frequency brain waves respond to psychedelics. Scientists might also expand the analysis to specific moments during the psychedelic experience. Tying specific bursts of visual imagery to real-time changes in brain criticality could provide a more detailed map of how human consciousness temporarily unravels.

The study, “DMT-induced shifts in criticality correlate with self-dissolution,” was authored by Mona Irrmischer, Marco Aqil, Lisa Luan, Tongyu Wang, Hessel Engelbregt, Robin Carhart-Harris, Klaus Linkenkaer-Hansen, and Christopher Timmermann.