Opposite network patterns of integration-segregation in psychedelic and sedated states of consciousness

Understanding the relationship of conscious states to large-scale brain dynamics remains a central challenge in neuroscience. Here, diverse pharmacological and physiological perturbations-including psychedelics, sleep, and propofol sedation-are used to examine integration-segregation organization of brain networks across altered states of consciousness in humans using functional MRI. Across analyses, psychedelic and sedative states exhibit a robust "mirror-image" pattern of integration and segregation. Psychedelics are characterized by increased large-scale integration and reduced segregation of brain network interactions, whereas sleep and propofol sedation show the opposite configuration. These divergent integration-segregation patterns are indexed by complementary measures of functional connectivity, network topology, and interaction complexity, capturing non-redundant dimensions of large-scale brain organization. Importantly, this mirror-image organization generalizes across multiple spatial levels and reliably differentiates conscious states through unbiased, data-driven methods. Together, these findings demonstrate that psychedelic and sedated states are characterized by systematic and opposite shifts in large-scale integration and segregation, with implications for mechanisms of consciousness.