Opposing 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 psychedelic states, sleep, and propofol sedation--were 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 exhibited a robust "mirror-image" pattern of integration and segregation. Psychedelics were characterized by increased large-scale integration and reduced segregation of brain network interactions, whereas sleep and propofol sedation showed the opposite configuration. These opposing integration-segregation patterns were consistently 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 generalized across multiple spatial levels and reliably differentiated conscious states in an unbiased, data-driven manner. Together, these findings demonstrate that psychedelic and sedated states are characterized by systematic and opposing shifts in large-scale integration and segregation, with implications for mechanisms of consciousness.