Effects of the South American Psychoactive Beverage Ayahuasca on Regional Brain Electrical Activity in Humans: A Functional Neuroimaging Study Using Low-Resolution Electromagnetic Tomography
- 1 June 2004
- journal article
- clinical trial
- Published by S. Karger AG in Neuropsychobiology
- Vol. 50 (1), 89-101
- https://doi.org/10.1159/000077946
Abstract
Ayahuasca, a South American psychotropic plant tea obtained from Banisteriopsis caapi and Psychotria viridis, combines monoamine oxidase-inhibiting β-carboline alkaloids with N,N-dimethyltryptamine (DMT), a psychedelic agent showing 5-HT2A agonist activity. In a clinical research setting, ayahuasca has demonstrated a combined stimulatory and psychedelic effect profile, as measured by subjective effect self-assessment instruments and dose-dependent changes in spontaneous brain electrical activity, which parallel the time course of subjective effects. In the present study, the spatial distribution of ayahuasca-induced changes in brain electrical activity was investigated by means of low-resolution electromagnetic tomography (LORETA). Electroencephalography recordings were obtained from 18 volunteers after the administration of a dose of encapsulated freeze-dried ayahuasca containing 0.85 mg DMT/kg body weight and placebo. The intracerebral power density distribution was computed with LORETA from spectrally analyzed data, and subjective effects were measured by means of the Hallucinogen Rating Scale (HRS). Statistically significant differences compared to placebo were observed for LORETA power 60 and 90 min after dosing, together with increases in all six scales of the HRS. Ayahuasca decreased power density in the alpha-2, delta, theta and beta-1 frequency bands. Power decreases in the delta, alpha-2 and beta-1 bands were found predominantly over the temporo-parieto-occipital junction, whereas theta power was reduced in the temporomedial cortex and in frontomedial regions. The present results suggest the involvement of unimodal and heteromodal association cortex and limbic structures in the psychological effects elicited by ayahuasca.Keywords
This publication has 20 references indexed in Scilit:
- Human Pharmacology of Ayahuasca: Subjective and Cardiovascular Effects, Monoamine Metabolite Excretion, and PharmacokineticsJournal of Pharmacology and Experimental Therapeutics, 2003
- Topographic pharmaco‐EEG mapping of the effects of the South American psychoactive beverage ayahuasca in healthy volunteersBritish Journal of Clinical Pharmacology, 2002
- Localization of MDMA‐induced brain activity in healthy volunteers using low resolution brain electromagnetic tomography (LORETA)Human Brain Mapping, 2001
- Psychometric assessment of the Hallucinogen Rating ScaleDrug and Alcohol Dependence, 2001
- Agonist Properties of N,N-Dimethyltryptamine at Serotonin 5-HT2A and 5-HT2C ReceptorsPharmacology Biochemistry and Behavior, 1998
- Differential psychopathology and patterns of cerebral glucose utilisation produced by (S)- and (R)-ketamine in healthy volunteers using positron emission tomography (PET)European Neuropsychopharmacology, 1997
- Nonparametric Analysis of Statistic Images from Functional Mapping ExperimentsJournal of Cerebral Blood Flow & Metabolism, 1996
- Multiband topographic EEG analysis of a simulated visuomotor aviation taskInternational Journal of Psychophysiology, 1994
- Mescaline-induced psychopathological, neuropsychological, and neurometabolic effects in normal subjects: Experimental psychosis as a tool for psychiatric researchBiological Psychiatry, 1992
- Normal nucleolar size of entorhinal cortex cells in SchizophreniaPsychiatry Research, 1992