Network Rerouting Under Ayahuasca: Temporally and Hemisphere-Resolved EEG Connectomics
bioRxiv (Cold Spring Harbor Laboratory) December 11, 2025 Caroline L. Alves, Fernanda Palhano-Fontes, Thaise G. L. de O. Toutain et al.
Ayahuasca alters conscious experience, and this study identifies EEG markers of its network-level effects using machine learning and complex-network analysis. In a randomized, double-blind, placebo-controlled trial with naïve ayahuasca users, resting-state EEG was recorded before dosing, 2 hours after, and 4 hours after. Connectivity was estimated with sliding windows; optimal classification performance occurred at 60–70 seconds (AUC and accuracy = 0.93). Network analysis revealed a bilateral decrease in eigenvector centrality (weaker hub influence), increased degree heterogeneity in the right hemisphere, and reduced global efficiency in the left. Posterior-left connections weakened acutely, while right temporal–central coupling transiently strengthened. The findings suggest that hub-centric shortcuts weaken, routing communication through more distributed, less efficient pathways with right-lateralized expression.