Differential Cortical Network Engagement During States of Un/Consciousness

Abstract

The neural basis of consciousness remains a major unresolved issue in human neuroscience. To better understand how cortical networks are engaged during different states of consciousness, we utilized multi-region intracranial single-pulse direct electrical stimulation to examine circuit and network interactions during three canonical states of consciousness: wake, sleep, and under propofol-induced general anesthesia. Increased variability in cortical responses, reduced information transfer, and reduced complexity characterized states of diminished consciousness. Notably, however, these metrics differed in different brain regions and types of unconscious states. Anesthesia induced more overall changes in brain responses than sleep. Brain activity changes were largely anatomically uniform during sleep, contrasting with a substantial and selective disconnection of the prefrontal cortices during anesthesia. These results suggest that the obliteration of consciousness during anesthesia results not from just altered overall physiology but from a disconnection between prefrontal areas and other brain areas.