Psilocybin acutely reduces low-frequency BOLD power and frequency-specific connectivity
Olsen, A. S.; Larsen, K.; McCulloch, D. E.-W.; Ganz, M.; Madsen, M. K.; Ozenne, B.; Knudsen, G. M.; Rehman, N. u.; Fisher, P. M.
Show abstract
Psilocybin and other serotonergic drugs acutely alter human brain function and large-scale connectivity as measured with BOLD fMRI, but whether these effects are frequency-specific remains unknown. We applied multitaper spectral and cross-spectral analyses to resting-state fMRI data from 28 healthy volunteers scanned multiple times acutely following oral psilocybin administration (0.2 - 0.3 mg/kg), together with plasma psilocin measurements, to estimate psilocin associations with temporal frequency-specific activity and connectivity. Psilocybin produced a selective reduction in low-frequency spectral power (0.01 - 0.06Hz) and an increase in spectral entropy, with the strongest effects in transmodal networks. We also observed a reduction in low-frequency connectivity energy explained by the unimodal/transmodal axis. These findings demonstrate that psilocin induces spatially distributed, frequency-dependent alterations, suggesting that broadband fMRI analyses may obscure low-frequency dynamics. Frequency-resolved approaches may offer greater sensitivity for characterizing psychedelic effects on brain activity.
Matching journals
The top 3 journals account for 50% of the predicted probability mass.