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LSD Reconfigures Cortical Dynamics Through Faster Brain Rhythms and Increased Fractal Dimension

Venkatesh Subramani, Timothy Nest, Annalisa Pascarella, Jérémy Brunel, Yorguin Jose Mantilla Ramos, Yann Harel, S. Muthukumaraswamy, Robin Carhart-Harris, Giulia Lioi, Nicolas Farrugia, Karim Jerbi

bioRxiv (Cold Spring Harbor Laboratory) January 29, 2026 preprint DOI: 10.64898/2026.01.28.702361 (opens in new tab)

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Study at a glance

AI-extracted from the abstract
Characteristics Placebo-controlled trial with music condition
Population Human participants
Intervention Lysergic acid diethylamide (LSD)
Topics LSD
Keywords Magnetoencephalography Aperiodic graph Rhythm Electrophysiology Dynamics music Neural activity Fractal dimension Electroencephalography Local field potential Neurophysiology Artificial intelligence Human brain Spectral analysis Flattening Neural ensemble
Citations 1
Key findings LSD induces spatially structured increases in alpha and beta peak frequencies alongside genuine attenuation of oscillatory power, flattens the aperiodic 1/f slope, and increases neural signal fractality and complexity, with music not amplifying these effects.

Abstract

Abstract Lysergic acid diethylamide (LSD) profoundly alters conscious experience, yet the electrophysiological mechanisms by which it reshapes neural dynamics remain incompletely understood. A hallmark of psychedelic states is widespread cortical desynchronization, typically inferred from reductions in spectral power, but whether such effects reflect genuine weakening of neural oscillations or are confounded by shifts in oscillatory peak frequencies remains unresolved. Here, we address this gap by combining source-resolved magnetoencephalography (MEG), spectral parameterization, temporal complexity metrics, and interpretable machine learning in an LSD versus placebo design, with and without music. We show that LSD induces robust, spatially structured increases in alpha and beta peak frequencies alongside genuine attenuation of oscillatory power, with these effects displaying partly dissociable cortical patterns. Beyond rhythmic activity, LSD is associated with flattening of the aperiodic 1/f spectral slope and increased neural signal fractality and complexity, preferentially affecting sensory, language, emotion, and imagery-related networks while sparing motor cortex. Machine-learning analyses further identify peak-frequency shifts, aperiodic parameters, and complexity measures as key discriminators of the psychedelic state. Music does not robustly amplify these neural signatures and instead shows a trend toward attenuation. Together, these findings provide a comprehensive electrophysiological account of how LSD reorganizes large-scale human brain dynamics and highlight features that may differentiate its neural signature from that of other psychedelics.

Comparable studies

Other randomized controlled trials on LSD, most cited first.

Study Year Design Participants
Safety and Efficacy of Lysergic Acid Diethylamide-Assisted Psychotherapy for Anxiety Associated With Life-threatening Diseases Patients with anxiety associated with life-threatening diseases 2014 Randomized controlled trial n = 12
Dose-Response Study of N,N-Dimethyltryptamine in Humans Experienced hallucinogen users 1994 Double-blind, saline placebo-controlled, randomized study n = 12
Acute Effects of Lysergic Acid Diethylamide in Healthy Subjects Healthy subjects (8 women, 8 men) 2014 Double-blind, randomized, placebo-controlled, crossover study n = 16
Changes in global and thalamic brain connectivity in LSD-induced altered states of consciousness are attributable to the 5-HT2A receptor Healthy human participants 2018 Double-blind, randomized, counterbalanced, cross-over study n = 24
LSD-induced entropic brain activity predicts subsequent personality change. Healthy adults 2016 Balanced-order, placebo-controlled study n = 19

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LSD Altered states of consciousness Mystical experience