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Previous issue date: 2017-07-27 / A ayahuasca ? uma bebida com propriedades psicod?licas amplamente utilizada por popula??es ind?genas da regi?o amaz?nica. Esse preparo cont?m a triptamina psicod?lica N,N-dimetiltriptamina (DMT), e inibidores da monoamina oxidase (iMAO), como harmina e harmalina. A ayahuasca ? considerada um psicod?lico seroton?rgico, e que pode levar a um estado alterado de consci?ncia com semelhan?as a uma experi?ncia on?rica, com intensas altera??es na percep??o, pensamentos, humor, emo??o, e experi?ncias tidas como m?sticas. Correlatos neurais dos efeitos agudos da ayahuasca t?m sido investigados por diferentes t?cnicas de neuroimagem funcional, incluindo a eletroencefalografia (EEG). Neste trabalho exploramos mudan?as espectrais de EEG em 50 volunt?rios saud?veis, utilizando desenho randomizado duplo-cego placebo-controlado. Metade recebeu uma sess?o com a ayahuasca, a outra metade com placebo. Ap?s a administra??o da subst?ncia, os volunt?rios foram monitorados durante 4 horas por um equipamento de EEG. A fim de melhorar a qualidade dos dados, os volunt?rios foram solicitados a realizar 2 tarefas simples em tr?s instantes espec?ficos: antes da ingest?o, 2h e 4 horas ap?s a ingest?o. Na primeira tarefa, deveriam tentar permanecer acordados, e intercalar per?odos de 20 segundos de olhos abertos, e 40 segundos de olhos fechados, durante 5 minutos. Na segunda tarefa, eles deveriam permanecer de olhos fechados, tentando se manter acordados, por outros 5 minutos. A an?lise espectral (2h) revelou que a pot?ncia de alfa ? significativamente menor no grupo ayahuasca que no placebo nas regi?es occipital e temporoparietal ? direita. Encontramos, ainda, aumento significativo em 2h na pot?ncia de teta na regi?o temporoparietal ? direita. A an?lise de correla??o revelou correspond?ncias entre a pot?ncia de alfa (2h) e a pontua??o obtida em duas escalas sens?veis aos efeitos de psicod?licos - a Hallucinogen Rating Scale (HRS) e o Mystical Experience Questionnaire (MEQ). Apresentamos, ainda, achados de tra?ados curiosos, encontrados na inspe??o visual dos tra?ados de EEG. De modo geral, nossos resultados sugerem que a inibi??o das oscila??es alfa em regi?es posteriores do c?rebro desempenha papel importante na experi?ncia psicod?lica, talvez compartilhando mecanismos presentes durante a experi?ncia on?rica. / Ayahuasca is a brew with psychedelic properties largely used by indigenous populations from the Amazon basin. It contains the psychedelic tryptamine N,N-dimethyltriptamine (DMT), and monoamine oxidase inhibitors (iMAO), such as harmine and harmaline. Ayahuasca is consid-ered to be a serotonergic psychedelic, capable of inducing an altered state of consciousness with similarities to an oneiric experience, with intense alterations in perception, though, humor, emo-tion, and mystical-type experiences. The neural correlates of its acute effects have been inves-tigated by different neuroimaging techniques, including electroencephalography (EEG). In this study, we explored EEG spectral changes in 48 healthy volunteers using a randomized double-blind placebo-controlled trial. Half of the volunteers received ayahuasca, half received placebo. We used an EEG system to monitor all volunteers throughout the dosing session, which lasted approximately 4-hours. Aiming to improve data quality, the volunteers were asked to perform two controlled tasks at three specific moments: before intake, 2h and 4h after intake. For the first task, they alternated moments of eyes open (20 seconds) with eyes closed (40 seconds) for 5 minutes, avoiding falling asleep. During the second task they should keep their eyes closed for another 5 minutes, again avoiding falling asleep. Spectral analysis at 2h after intake shows reduced alpha power, and increased theta and beta in the ayahuasca group with respect to the placebo, mainly in occipital and right temporoparietal regions. Correlation analysis revealed correspondences between the alpha power (2h) and individual scores on two scales used to measure psychedelic effects ? the Hallucinogen Rating Scale (HRS) and the Mystical Experi-ence Questionnaire (MEQ). Additionally, we also present EEG traces with electrophysiological events that might be of importance for the representation of the psychedelic experience. Over-all, our results suggest that the inhibition of alpha oscillations, increased theta and beta in right posterior brain regions play an important role on the psychedelic experience, maybe sharing mechanisms present during the oneiric experience.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/24291 |
| Date | 27 July 2017 |
| Creators | Pessoa, J?ssica de Andrade |
| Contributors | 50554310163, Miguel, Mario Andr? Leoc?dio, 29032018892, Tofoli, Luis Fernando Farah de, 14743602890, Andrade, Katia Cristine, Ara?jo, Draulio Barros de |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM NEUROCI?NCIAS, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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