Analogous cortical reorganization accompanies entry into states of reduced consciousness during anesthesia and sleep.
Cerebral cortex (New York, N.Y. : 1991) August 23, 2023 Bryan M Krause, Declan I Campbell, Christopher K Kovach et al.
Theories of consciousness propose that brain mechanisms for losing and regaining consciousness are similar regardless of cause. Using intracranial electroencephalography in neurosurgical patients during propofol anesthesia and overnight sleep, researchers found strikingly similar reorganization of cortical networks. Effective dimensionality of functional connectivity decreased during reduced consciousness (anesthesia unresponsiveness, N2 and N3 sleep), indicating lower network complexity. These changes were global, not region-specific. Brain regions became more functionally distant yet individual recording sites closer to nearest neighbors, reflecting decreased differentiation and integration. This network reorganization constitutes a common neural signature of reduced consciousness across anesthesia and sleep, providing a framework for understanding neural correlates of consciousness.