Time-resolved Neural and Experience Dynamics of Medium- and High-dose N,N-Dimethyltryptamine.
Apollo (University of Cambridge) December 30, 2025 Evan Lewis-Healey, Carla Pallavicini, Federico Cavanna et al.
A 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.