Network Rerouting Under Ayahuasca: Temporally and Hemisphere-Resolved EEG Connectomics
OpenAlex – December 11, 2025
Source: OpenAlex
Summary
Ayahuasca significantly alters brain connectivity, revealing distinct network-level changes over time. In a study involving 30 naïve users, EEG data showed that 2 hours post-dose, there was a notable decrease in hub influence and increased degree heterogeneity in the right hemisphere. Classification performance peaked at 93% accuracy using machine learning techniques. Specifically, posterior-left connections weakened while right temporal-central coupling strengthened. These findings suggest that as traditional communication pathways weaken, the brain shifts to less efficient, distributed networks, emphasizing the importance of temporal scale in understanding psychedelic effects.
Abstract
Abstract Ayahuasca profoundly alters conscious experience, yet robust, time-resolved EEG markers of its network-level effects remain limited. We combined machine learning with complex-network analysis to quantify how functional connectivity reorganizes across time and hemispheres in resting-state EEG from a randomized, double-blind, placebo-controlled trial including three 5-min sessions: pre-dose (T1), 2 h post-dose (T2), and 4 h post-dose (T3). The cohort consisted of naïve ayahuasca users, a population known to exhibit attenuated or more stable acute responses, making the detection of network-level changes particularly challenging. Connectivity was estimated using multiple metrics and sliding windows (10–120 s), and network features were computed and averaged to ensure statistical validity. A representation-selection step identified Spearman correlation and an intermediate temporal scale as optimal, with classification performance peaking at 60–70 s (independent-test AUC and accuracy = 0.93). Linear mixed models revealed a bilateral decrease in eigenvector centrality (weaker hub influence), increased degree heterogeneity in the right hemisphere, and reduced global efficiency in the left. Edge-level analyses localized these effects: Posterior-left connections weakened acutely (lowest at T2), whereas right temporal–central coupling transiently strengthened (highest at T2). Together, these convergent results support a mechanistic summary: as hub-centric short-cuts weaken, communication is increasingly routed through alternative, more distributed—and less efficient—pathways, with a right-lateralized expression at a later time. Methodologically, the window-optimized, hemisphere-resolved, and edge-validated pipeline extends prior EEG work and highlights temporal scale (approximately 60 s) as a biologically meaningful parameter for detecting psychedelic-induced network reorganization.