Connectome-harmonic decomposition of human brain activity reveals dynamical repertoire re-organisation under LSD

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.\n\nHighlightsO_LIIntroducing a novel connectome-harmonic decomposition of human brain activity, which is used to study the dynamics after administration of lysergic acid diethylamide (LSD)\nC_LIO_LILSD alters the total energy and power of individual harmonics in a frequency-selective manner and increases the size of the dynamical repertoire of these brain states\nC_LIO_LIThe repertoire expansion occurs in a non-random fashion suggesting a re-organization of brain dynamics at the edge of criticality\nC_LI