LSD flattens the hierarchy of directed information flow in fast whole-brain dynamics
bioRxiv (Cold Spring Harbor Laboratory) April 28, 2024 Kenneth Shinozuka, Prejaas Tewarie, Andrea I. Luppi et al. 5 citations preprint
LSD weakens the brain's directed connectivity hierarchy by increasing the balance between senders and receivers of neural signals. This finding supports the REBUS theory, which proposes that psychedelics flatten the hierarchy of information flow in the brain. Analyzing magnetoencephalography data from 16 healthy participants given 75 micrograms of intravenous LSD, the study found that LSD diminishes the asymmetry of directed connectivity averaged over time. Machine learning classifiers distinguished LSD from placebo more accurately when trained on hierarchy metrics than on traditional functional connectivity measures.