LSD-induced increase of Ising temperature and algorithmic complexity of brain dynamics
bioRxiv August 29, 2022 Giulio Ruffini, Giada Damiani, Diego Lozano-Soldevilla et al. 5 citations preprint
Using fMRI data from fifteen people who took LSD or a placebo, researchers modeled brain dynamics with an Ising spin model to test whether psychedelics push the brain into a more disordered state. LSD increased the Ising temperature of brain activity, moving it further away from a critical point (the edge between order and disorder) into a more disordered, paramagnetic phase. This shift was accompanied by a decrease in interhemispheric connectivity, especially between corresponding regions in the two hemispheres. Algorithmic complexity of brain signals also increased with LSD. The findings suggest LSD loosens homotopic connections, driving the brain into a more flexible, complex state, consistent with theories that psychedelics increase neural entropy.