Many users of the psychedelic drug dimethyltryptamine (DMT) report intense experiences. One of the feelings they most commonly go through is a loss of their sense of self, or “ego death”. Researchers interested in these drugs’ potential medical benefits, as well as those studying consciousness, have tried to pinpoint exactly what is happening in the brain during these experiences. A new study may have identified a brain signal that marks DMT-induced ego death.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.
The research team was led by the psychedelics researchers Christopher Timmermann, of University College London, and Marco Aqil, of the University of Miami. Previous findings in the field had suggested that some of the intense effects of psychedelics may work by altering our brain waves. In particular, the authors homed in on a specific dimension of these waves called criticality.
“Criticality refers to a brain state balanced between chaos and order that helps us predict things about the environment, the way we change or adapt to it, and our self-awareness,” said Timmermann in a press release. The complex brain wave oscillations that occur during criticality, write the authors, are thought to support our brains’ experience of consciousness over long periods.
In their new paper, the researchers wanted to explore how DMT alters criticality. They analyzed electroencephalographic (EEG) data from 27 participants who received DMT. EEG data allows researchers to noninvasively measure brain wave activity using electrode caps. They then combed the participants’ brain data for markers called long-range temporal correlations (LRTCs), which indicate brain activity that is close to criticality.
Their analysis showed that taking DMT caused alpha and theta brain waves, associated with relaxation and inward focus, to shift away from criticality into simpler oscillations. These shifts are similar to those caused by meditation and anesthesia. The strength of these shifts was correlated with the level of ego death that participants felt. The researchers say that this shift may explain why intense DMT trips disrupt our normal experience of coherent consciousness.
“We rely on past narratives and future predictions to have a coherent sense of self. In a DMT experience, people do not have a stream of consciousness over a period of time—everything takes place in the present moment,” said Aqil in a press release. “This shift in criticality signatures in the alpha frequency [during a DMT experience likely reveals how] the time-extended component of the sense of self is weakened.”
The team calls for research exploring how brainwave criticality changes during other subjective DMT trip experiences, such as intense visuals. The researchers noted that their findings of shifts toward subcriticality clashed with existing hypotheses of psychedelic action in the brain, like the entropic brain hypothesis that predicts that psychedelics should increase criticality.
The authors suggest that increased criticality might occur only for high-frequency gamma brainwaves, which are linked to intense focus and were not measured in this study. It’s a sign that researchers are only just beginning to understand the complex shifts that these drugs cause in our brains.
The study is published in the Journal of Neuroscience.
Source Link: “Ego Death”: How Psychedelics Trigger Meditation-Like Brain Waves
