Anesthesia-induced loss of consciousness disrupts auditory responses beyond primary cortex

Significance We studied how anesthesia-induced loss of consciousness (LOC) affects processing of external sensory events at single-neuron resolution in epilepsy patients implanted with depth electrodes for clinical treatment. Just before electrode removal, patients were lightly anesthetized with propofol while we presented sounds around LOC. We found that auditory responses were widespread across the brain during wakefulness. Upon LOC, robust responses persisted in primary auditory cortex while responses in high-order auditory regions were mostly attenuated. In addition, gamma power responses in local field potentials strengthened upon LOC, in contrast to spiking activities. The disruption in sensory signaling beyond primary cortices highlights impaired cortical connectivity as a key factor in LOC and may guide future development of anesthesia monitors and anesthetic agents.