After taking LSD, the brain's dynamics become less stable and more diverse in response to perturbations. Using a whole-brain computational model fitted to fMRI data from individuals under LSD or placebo, researchers simulated external disruptions to different brain regions. They measured recovery time with the Perturbational Integration Latency Index (PILI). Globally, LSD caused consistently higher PILI values, indicating a shift further from stable equilibrium. Locally, the largest differences appeared in the limbic, visual, and default mode networks. LSD also increased variability of PILI across brain regions, suggesting greater response diversity. These findings reveal brain-wide dynamical changes underlying the psychedelic state and suggest potential clinical applications for psychiatric disorders.
LSD alters brain dynamics by shifting the brain's global working point further from a stable equilibrium, as shown by consistently higher Perturbational Integration Latency Index (PILI) values after intake. Using a whole-brain computational model perturbed in silico, the largest differences were found in the limbic, visual, and default mode networks. Greater variability of PILI values across brain regions under LSD indicates higher response diversity to external perturbations. These findings provide insights into the brain-wide dynamical changes underlying the psychedelic state and suggest possible clinical applications for psychiatric disorders.