DMT-induced shifts in criticality correlate with self-dissolution.

A psychedelic substance (DMT) shifts brain oscillations away from criticality—a state of balanced, complex activity—toward a quieter subcritical regime, particularly in alpha and adjacent frequency bands. This shift increases entropy while reducing complexity. The magnitude of the criticality shift in alpha and theta bands correlates with the intensity of self-dissolution, a core feature of the psychedelic experience. These findings suggest that altered proximity to critical dynamics underlies both the neurological and experiential effects of psychedelics, with implications for understanding altered states of consciousness.

Study at a glance

Abstract

Psychedelics profoundly alter subjective experience and brain dynamics. Brain oscillations express signatures of near-critical dynamics, relevant for healthy function. Alterations in the proximity to criticality have been suggested to underlie the experiential and neurological effects of psychedelics. Here, we investigate the effects of a psychedelic substance (DMT) on the criticality of brain oscillations, and in relation to subjective experience, in humans of either sex. We find that DMT shifts the dynamics of brain oscillations away from criticality in alpha and adjacent frequency bands. In this context, entropy is increased while complexity is reduced. We find that the criticality shifts observed in alpha and theta bands correlate with the intensity ratings of self-dissolution, a hallmark of psychedelic experience. Finally, using a recently developed metric, the functional excitatory-inhibitory ratio, we find that the DMT-induced criticality shift in brain oscillations is towards subcritical regimes. These findings have major implications for the understanding of psychedelic mechanisms of action in the human brain and for the neurological basis of altered states of consciousness.Significance statement Criticality is characterized by fluctuations occurring on a wide range of spatiotemporal scales and high complexity. Here, we investigate the effects of DMT, a classic psychedelic, on criticality of brain oscillations and in relation to subjective experience. We find that DMT shifts the normally dominant alpha oscillations towards a quieter subcritical state, increasing entropy while reducing complexity, and that this shift correlates with intensity of disruption of the sense of self.