A growing body of brain-imaging research has mapped, with increasing precision, how the Amazonian psychedelic brew ayahuasca rewires electrical activity across the human brain. The latest contribution, a randomized, double-blind, placebo-controlled trial of 50 healthy volunteers published in the Journal of Psychopharmacology, tracked EEG oscillations at baseline and at two and four hours after a dose of 1 mL/kg of ayahuasca, finding that global alpha waves drop while frontomedial delta activity climbs. These results, combined with more than a decade of earlier EEG and fMRI work, are giving scientists their clearest picture yet of the neural signature behind ayahuasca’s intense visions and altered states of consciousness.
Public attention to these findings has grown alongside popular reporting on how the brew alters perception. One widely cited overview described how the psychedelic mixture disrupts normal brain patterns and appears to relax the usual constraints on sensory processing, echoing the laboratory evidence that cortical rhythms become less orderly in some bands and more synchronized in others. Together, the controlled experiments and journalistic accounts point to the same conclusion: ayahuasca does not simply “turn up the volume” of the mind, it reshapes how information flows through the cortex.
Alpha Waves Drop, Gamma Surges In
The most consistent finding across controlled ayahuasca studies is a sharp decline in alpha-band power, the 8 to 13 Hz rhythm that dominates a resting, eyes-closed brain. A 2015 study published in PLOS ONE tied this suppression to blood levels of ayahuasca alkaloids, reporting reduced alpha roughly 50 minutes after ingestion, followed by a surge in slow-gamma power between 30 and 50 Hz from about 75 to 125 minutes post-dose. That biphasic pattern, first quiet, then electrically loud, appears to track the subjective arc of the experience: initial disorientation giving way to vivid imagery, as if the brain is briefly stripped of its usual idling rhythm before higher-frequency networks bind new perceptions into a coherent narrative.
A separate receptor-level experiment sharpened the causal picture. Using ketanserin, a 5-HT2A serotonin receptor antagonist, researchers showed in a double-blind, placebo-controlled design that ayahuasca-related decreases in delta, theta, and alpha power depend heavily on activation of the 5-HT2A receptor, and that alpha-band current density links directly to the intensity of visual effects. Block that receptor and both the brain wave shift and the hallucinations weaken in tandem. This is one of the strongest pieces of evidence that the visual component of the ayahuasca experience is not a side effect but a direct product of serotonergic disruption, with cortical pyramidal cells changing their firing patterns in ways that EEG can capture as a loss of slow rhythms and a rise in faster, more irregular activity.
How Information Flow Rewires Under the Brew
Power changes in individual frequency bands tell only part of the story, because they do not reveal which regions drive the conversation. A double-blind, randomized, balanced crossover study applied transfer entropy, a mathematical tool that measures the direction of information flow between brain regions, and found that serotonergic psychedelics temporarily modify information transfer in the human brain. In that work, ayahuasca and related compounds altered how anterior and posterior regions communicate, supporting the idea that top-down control from frontal areas relaxes while bottom-up sensory signals gain influence. In phenomenological terms, filters that normally suppress internally generated images loosen, allowing memories, emotions, and spontaneous visual scenes to push into awareness.
Parallel fMRI evidence reinforces this interpretation. Previous functional MRI studies of psychedelics have found decreased within-network integrity alongside increased between-network global connectivity, meaning the brain’s usual compartmentalized processing breaks down while distant regions start talking to each other in unusual ways. Under ayahuasca, association cortices that ordinarily keep sensory, emotional, and autobiographical material in separate lanes instead display a more globally integrated pattern of activity. The combination of loosened internal networks and heightened cross-talk helps explain why users often describe the state as dreamlike yet hyper-real, a condition in which boundaries blur but metacognitive awareness is not entirely lost.
Gamma Coherence and the Ritual Setting
Laboratory conditions, with their neutral rooms and standardized doses, strip away the ceremonial context in which ayahuasca has been consumed for centuries. Field EEG research conducted with Santo Daime ritual participants found increases in 36 to 44 Hz power in posterior electrodes, with alkaloid composition measurements of sampled doses recording milligram amounts of harmine, THH, DMT, harmaline, and harmol. An earlier exploratory study also reported increases in global coherence in high-frequency bands spanning 36 to 44 Hz and 50 to 64 Hz during visual imagery compared to an eyes-closed baseline, indicating that gamma-band synchronization intensifies when participants report the most elaborate inner scenes. These gamma coherence spikes suggest that the brain is not simply chaotic under ayahuasca; it is coordinating at high frequencies in ways that correlate with the richness of subjective visual experience.
The ritual data raises a question that lab-only research cannot fully answer. Ceremonial participants ingest a full botanical brew whose alkaloid profile varies batch to batch, sing specific chants, and sit in darkness for hours, all factors that may shape both mood and neural dynamics. Whether the gamma coherence observed in those settings exceeds what controlled doses produce in a quiet hospital room is still unclear, because no single study has directly compared the two environments with matched EEG protocols. For clinicians hoping to translate ayahuasca’s neural effects into standardized therapy, that gap underscores the importance of “set and setting”: the brain waves recorded in a scanner may not fully capture the patterns that emerge when music, community, and expectation interact with the pharmacology of the brew.
From Brain Waves to Therapy
The newest trial, involving 50 healthy volunteers in a parallel-arm design, found that ayahuasca compared to placebo induced positive emotionality measured by the HRS Happy subscale, alongside the expected global alpha decreases and frontomedial delta increases at the two- and four-hour EEG checkpoints. By pairing these oscillatory changes with standardized mood outcomes, the researchers could begin to map which electrical signatures align with beneficial shifts in affect. In this dataset, greater alpha suppression and delta enhancement tracked with higher ratings of well-being and emotional openness, hinting that specific patterns of cortical disinhibition and slow-wave recruitment might serve as biomarkers for therapeutic response.
These findings arrive amid broader public and institutional interest in psychedelic-assisted interventions. Media organizations that have followed the field closely now offer dedicated science coverage and subscription products, inviting readers who follow stories on ayahuasca and other compounds to support ongoing reporting through options such as a weekly print subscription or other contribution models. As clinical trials expand, the bridge between technical EEG metrics and public understanding will likely depend on this kind of sustained explanatory journalism as much as on the raw data emerging from laboratories.
Ethics, Access, and the Road Ahead
While the neurophysiology of ayahuasca is becoming clearer, questions about access, ethics, and commercialization are only beginning to be addressed. Indigenous communities in the Amazon have developed ceremonial frameworks that contextualize the brew’s powerful psychological effects, and many researchers argue that any medical use should respect this cultural heritage. At the same time, international interest has spawned retreat centers, underground therapy circles, and a nascent industry of psychedelic services, creating a landscape in which scientific rigor, spiritual practice, and profit motives can collide. How regulators and professional bodies respond will influence not only who receives treatment, but also how safely and equitably it is delivered.
Institutions that cover and participate in this transition are building infrastructures around participation and support. Readers who want to follow developments in psychedelic science more closely can create dedicated news accounts through services such as a streamlined digital sign-in portal, while others choose to underwrite independent reporting via general contribution platforms, including membership-style support pages. As psychedelic research laboratories, clinics, and media desks grow, they also rely on a widening pool of specialized staff, with recruitment often advertised through sector-spanning job boards such as a dedicated careers site. In parallel with the evolving science of brain waves and consciousness, these social and institutional networks will help determine how knowledge about ayahuasca is produced, interpreted, and ultimately woven into mainstream healthcare.
More from Morning Overview
*This article was researched with the help of AI, with human editors creating the final content.
