Effects of Ayahuasca on the human EEG
Phytomedicine April 1, 1998 Neville S. Arachchige Don, Bruce E. Mcdonough, Gabriel Acácio de Moura et al. 33 citations
Ayahuasca ingestion increased 36-44 Hz ("40 Hz") brain wave power in posterior scalp regions, consistent with intensified visual imagery. The study recorded EEG from 11 members of the Santo Daime Doctrine before and after drinking ayahuasca. Power increases appeared from left occipital-temporal-parietal electrodes with eyes closed and spread across most of the posterior scalp with eyes open. Slow theta and alpha rhythms tended to decrease, while 14-30 Hz beta power increased. Analysis of four ayahuasca samples showed average doses of 55.6 mg harmine, 43.9 mg tetrahydroharmine, 41.3 mg DMT, 4.6 mg harmaline, and 3.1 mg harmol per 75 ml. The DMT concentration was sufficient for psychoactive effects, with β-carbolines providing MAO inhibition to maintain oral activity.