Increased frontal and paralimbic activation following ayahuasca, the pan-amazonian inebriant
Jordi Riba, Sergio Romero, Eva Grasa, Esther Mena, Ignasi Carrió, Manel J. Barbanoj
Psychopharmacology March 30, 2006 DOI: 10.1007/s00213-006-0358-7 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Randomized controlled trial Double-blind Peer reviewed |
|---|---|
| Sample size | 15 |
| Population | Male volunteers with prior experience in the use of psychedelics |
| Intervention | Ayahuasca |
| Dose | 1.0 mg DMT/kg body weight |
| Topics | Ayahuasca Serotonin |
| Keywords | Parahippocampal gyrus Hallucinogen Anesthesia |
| Citations | 245 |
| Key findings | Ayahuasca administration increased regional cerebral blood flow in frontal and paralimbic brain regions, including the anterior insula, anterior cingulate/frontomedial cortex, and left amygdala/parahippocampal gyrus. |
Abstract
RationaleAyahuasca is a South American psychoactive plant tea which contains the serotonergic psychedelic N,N-dimethyltryptamine (DMT) and monoamine-oxidase inhibitors that render DMT orally active. Previous investigations with ayahuasca have highlighted a psychotropic effect profile characterized by enhanced introspective attention, with individuals reporting altered somatic perceptions and intense emotional modifications, frequently accompanied by visual imagery. Despite recent advances in the study of ayahuasca pharmacology, the neural correlates of acute ayahuasca intoxication remain largely unknown.ObjectivesTo investigate the effects of ayahuasca administration on regional cerebral blood flow.MethodsFifteen male volunteers with prior experience in the use of psychedelics received a single oral dose of encapsulated freeze-dried ayahuasca equivalent to 1.0 mg DMT/kg body weight and a placebo in a randomized double-blind clinical trial. Regional cerebral blood flow was measured 100-110 min after drug administration by means of single photon emission tomography (SPECT).ResultsAyahuasca administration led to significant activation of frontal and paralimbic brain regions. Increased blood perfusion was observed bilaterally in the anterior insula, with greater intensity in the right hemisphere, and in the anterior cingulate/frontomedial cortex of the right hemisphere, areas previously implicated in somatic awareness, subjective feeling states, and emotional arousal. Additional increases were observed in the left amygdala/parahippocampal gyrus, a structure also involved in emotional arousal.ConclusionsThe present results suggest that ayahuasca interacts with neural systems that are central to interoception and emotional processing and point to a modulatory role of serotonergic neurotransmission in these processes.