Connectome-harmonic decomposition of human brain activity reveals dynamical repertoire re-organization under LSD
Atasoy, S., Carhart-Harris, R. L., Deco, G., Kaelen, M., Kringelbach, M. L., Roseman, L.
This placebo-controlled within-subjects study (n=12) analysed fMRI data of participants' brain activity in response to LSD (75μg/70kg) with or without the influence of listening to music. Using a novel connectome-specific harmonic decomposition method, they found that brain states under the influence of LSD exhibit a wider and more flexible repertoire of activation patterns, which maintain a unique type of non-random stability in their co-activation over time.
Abstract
Introduction: 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.Methods: Here we used ’connectome-harmonic decomposition’, a novel method to investigate the dynamical changes in brain states.Results: 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.Discussion: Beyond the present findings, these methods open up for a better understanding of the complex brain dynamics in health and disease.