Time-resolved Neural and Experience Dynamics of Medium- and High-dose N,N-Dimethyltryptamine.
Evan Lewis-Healey, Carla Pallavicini, Federico Cavanna, Tomás Ariel D'Amelio, Laura Alethia de la Fuente, Debora Copa, Stephanie Müller, Nicolás Bruno, Enzo Tagliazucchi, T. Bekinschtein
Apollo (University of Cambridge) December 30, 2025 DOI: 10.17863/cam.124823 via OpenAlex
Summary
AI-generated from the abstractA dose of the fast-acting psychedelic drug DMT rapidly reorganizes both conscious experience and brain activity. In a blinded, counterbalanced study, 19 participants received either 20 mg or 40 mg of freebase DMT. The higher dose caused more extreme visual hallucinations and emotionally intense experiences. Electroencephalography showed that changes in alpha brainwave power and a measure of signal irregularity (permutation entropy) were most strongly linked to moment-by-moment changes in subjective experience. Surprisingly, a measure of neural signal complexity (Lempel-Ziv complexity), previously thought to be a robust marker of psychedelic states, showed the weakest link to experience. This suggests the connection between brain complexity and conscious experience during psychedelic states is less straightforward than previously assumed.
Study at a glance
| Characteristics | Repeated-measures dose-dependent study Peer reviewed |
|---|---|
| Sample size | 19 |
| Population | Human participants |
| Interventions | N N-dimethyltryptamine (DMT) |
| Dose | 20 mg or 40 mg |
| Keywords | Electroencephalography Neural activity Dynamics music Phenomenology philosophy Alpha rhythm |
| Key finding | Oscillatory alpha power and permutation entropy were most strongly associated with continuous subjective experience dimensions during DMT-induced states, while Lempel-Ziv complexity yielded the weakest associations. |
Abstract
N,N-dimethyltryptamine (DMT) is a fast-acting psychedelic drug that induces a radical reorganization of conscious contents and brain dynamics. However, our understanding of how brain dynamics support psychedelic-induced conscious states remains unclear. We therefore present a repeated-measures dose-dependent study of the subjective and neural dynamics induced through DMT under naturalistic conditions. Nineteen participants received either a 20-mg or a 40-mg dose of freebase DMT across two sessions in a blinded, counterbalanced order. Electroencephalography data and time-resolved measures of subjective experience (Temporal Experience Tracing) were collected. Both doses of DMT induced rapid changes in experience dimensions, with the 40-mg dose inducing more extreme visual hallucinations and emotionally intense experiences. A variety of neural features were computed on the electroencephalography data, with oscillatory alpha power and permutation entropy most strongly associated with continuous subjective experience dimensions. Strikingly, Lempel-Ziv complexity, previously hailed as a robust correlate of subjective experiences within the psychedelic state, yielded the weakest associations. These findings suggest that the relationship between neural complexity and phenomenology in psychedelic states is less clear than originally hypothesized.