Classic serotonergic psychedelics strongly alter conscious awareness, but how they change the temporal structure of brain activity has been unclear. In a double-blind, placebo-controlled study with 25 participants using high-density EEG, an ayahuasca-inspired formulation (intranasal N,N-DMT and buccal harmine) accelerated neural dynamics: microstate duration decreased and state transitions became more frequent. Surprisingly, the sequence of microstates became less random, showing higher first-order Markov structure. This restructuring involved reduced transitions into one state (M2) and increased prevalence and accessibility of two others (M3 and M5). The psychedelic state thus produces a syntactically reconfigured, highly metastable neural dynamic, not mere randomization.
A psychedelic formulation combining DMT and harmine, inspired by ayahuasca, blurs the brain's distinction between self and other faces. In a double-blind, placebo-controlled experiment with 31 healthy men, the DMT/harmine combination increased early visual brain responses (P1 amplitude) and disrupted the structural encoding of faces (reduced N170 amplitude) for all face types. It also specifically reduced the brain's later response (P300) to one's own face, making the neural reaction to self-faces more similar to that for familiar or unknown faces. Harmine alone did not produce these effects. The findings suggest psychedelics may reduce attentional focus on self-referential information, potentially explaining feelings of unity and enhanced empathy.