Recent studies have started to elucidate the effects of lysergic acid diethylamide (LSD) on the human brain but the underlying dynamics are not yet fully understood. Here we used ’connectome-harmonic decomposition’, a novel method to investigate the dynamical changes in brain states. We found that LSD alters the energy and the power of individual harmonic brain states in a frequency-selective manner. Remarkably, this leads to an expansion of the repertoire of active brain states, suggestive of a general re-organization of brain dynamics given the non-random increase in co-activation across frequencies. Interestingly, the frequency distribution of the active repertoire of brain states under LSD closely follows power-laws indicating a re-organization of the dynamics at the edge of criticality. Beyond the present findings, these methods open up for a better understanding of the complex brain dynamics in health and disease.

The authors would like to thank Andrea Insabato for valuable discussions on significance analysis. This work and S.A. are supported by Programa Beatriu de Pinos 2014 BP-B 00270. L.R., M.K. and R.L.C.H. are supported by Beckley foundation. G.D. is supported by the ERC Advanced Grant: DYSTRUCTURE (no 295129), by the Spanish Research Project PSI2016-75688-P (AEI/FEDER), by the European Union’s Horizon 2020 research and innovation programme under grant agreement no 720270 (HBP SGA1). M.L.K. is supported by the ERC Grant: CAREGIVING (no 615539). Part of this work was supported by Walacea crowd funding campaign.