How LSD Speeds Up Brain Rhythms and Alters Neural Activity

Lysergic acid diethylamide speeds up the brain’s alpha and beta rhythms rather than weakening them, according to an international study published Oct. 7, 2026, in the journal Communications Biology. First synthesized in a laboratory in 1938 by Swiss chemist Albert Hofmann, LSD is one of the most potent and most extensively studied psychedelics.

Alpha And Beta Waves Accelerate Across The Cortex

Seventeen healthy volunteers received an intravenous injection of 75 micrograms of LSD or a placebo in two sessions separated by two weeks. Researchers used magnetoencephalography to record tiny magnetic fields produced by neuronal activity down to the millisecond. The analysis revealed that alpha waves increase by about 2 hertz and beta waves by about 5 hertz across large areas of the cortex under the influence of LSD.

That acceleration contrasts with certain anesthetics that slow down the alpha rhythm. Imagine a radio station switching its broadcast frequency from 99.5 to 100.5 FM, Karim Jerbi, a professor in the Department of Psychology at the Université de Montréal and researcher at Mila – the Quebec Artificial Intelligence Institute, said. If your radio stays tuned to 99.5, the signal may seem distorted or lost. In the same way, overlooking the shift to faster brain rhythms can lead us to misinterpret LSD’s effects on the brain.

Signal Fractal Dimension Rises In Sensory And Emotional Regions

Beyond speed changes, the study found that LSD makes brain activity more complex, irregular, and fractal. The researchers measured this fractal dimension by observing how signals recur in patterns across different time scales, comparing the structural shift to the jagged outline of a rocky coastline where every zoom reveals new coves. Those shifts concentrate primarily in brain regions handling sensory perception, language, emotion, and mental imagery, while leaving the motor cortex relatively unaffected.

To test the distinctiveness of these patterns, the research team trained an artificial intelligence algorithm on the magnetoencephalography data. By combining multiple signal measures, the machine-learning model distinguished brain states under LSD from placebo sessions correctly 88 per cent of the time. Venkatesh Subramani, a doctoral student at the Université de Montréal and co-author of the study, noted that examining the clues used by the algorithm helps identify unique signatures in brain activity.

Therapeutic Trials Evaluate Formulations For Anxiety And Depression

Although the study tested a single dose in healthy volunteers without measuring therapeutic outcomes, the findings offer insight into proposed mechanisms for psychiatric treatments. Psychedelics may loosen rigid brain expectations, creating temporary flexibility that could help patients with depression and anxiety break out of repetitive thought loops. A formulation of LSD is currently undergoing phase 3 clinical trials for generalized anxiety disorder and depression.

Subramani and colleagues are continuing their work by comparing the neural effects of LSD against psilocybin and DMT. Funding for the original research was provided by the Natural Sciences and Engineering Research Council of Canada, Karim Jerbi’s Canada Research Chair, the Safra Foundation, the Beckley Foundation, and a crowdfunding campaign on the Walacea platform.