Human Brain Mapping
September 16, 2011
Dráulio Barros de Araújo, Sidarta Ribeiro, Guillermo Cecchi et al.
241 citations
Ayahuasca, a hallucinogenic brew containing serotonergic agonists and reuptake inhibitors, triggers vivid visual imagery during ceremonies. Using functional magnetic resonance imaging while participants performed a closed-eyes imagery task, the brew produced a robust increase in activation across occipital, temporal, and frontal brain areas. In the primary visual area, activation levels matched those of natural image viewing with eyes open. This effect correlated with individual perceptual changes measured by psychiatric scales. Activity in areas BA30 and BA37, linked to episodic memory and contextual associations, was also potentiated. Modulation of BA10, involved in prospective imagination and working memory, was detected. The findings suggest Ayahuasca seeings arise from an extensive network for vision, memory, and intention, lending a sense of reality to inner experiences.
Frontiers in Human Neuroscience
June 2, 2016
Fabiana M. Carvalho, Khallil Taverna Chaim, Tiago Arruda Sanchez et al.
26 citations
Updating internal models to predict future events relies on both frontal and parietal brain regions involved in uncertainty-driven updating and a separate network for temporal attention. Using fMRI, this study examined how continuous manipulation of temporal prediction engages these networks. Participants viewed periodic (simple harmonic oscillation) and non-periodic (variable acceleration) motion patterns. Non-periodic motion activated the exogenous temporal orienting network, including ventral premotor and inferior parietal cortices, cerebellum, presupplementary motor area, and motion-sensitive area MT+, with a right-hemisphere bias suggesting explicit timing. Periodic motion activated default-mode network midline areas (left DMPFC, ACC, bilateral PCC/PC), indicating the DMN may process contextually expected information and validate prospective internal models. Findings show continuous temporal prediction engages both temporal expectation representations and task-independent internal model updating.
Journal of magnetic resonance imaging : JMRI
December 1, 2025
Lucas Rego Ramos, Orlando Fernandes, Tiago Arruda Sanchez
1 citation
Long-term ayahuasca use may be associated with altered emotional brain reactivity and increased psychological resilience. In a study of 38 healthy male participants (19 long-term ayahuasca users and 19 non-user controls), users showed significantly higher resilience scores (mean = 43.89) compared to controls (mean = 39.05). A machine learning classifier distinguished users from controls with 75% accuracy, and a regression model significantly predicted individual resilience scores. These findings support neural patterns consistent with long-term adaptations from ayahuasca detectable via fMRI and machine learning.
Jornal Brasileiro de Psiquiatria
January 1, 2024
Dráulio Barros de Araújo, Tiago Arruda Sanchez, Sidarta Ribeiro
1 citation
Psychedelic substances have been used by humanity for millennia to induce non-ordinary states of consciousness, characterized by heightened sensory, emotional, and cognitive experiences, including augmented visual imagery, altered perception of space-time and reality, and profound mystical insights. Many indigenous populations worldwide developed these substances as vital components of healing. In the Amazon, shamans ancestrally used Ayahuasca, a drink made from two plants, to promote physical and psychological healing. The Navajo in North America retain the ancestral use of the peyote cactus as sacred medicine, while the Mazatecs of Mexico used psilocybin-containing mushrooms in their healing rituals.