Neurobiological Parallels, Overlaps, and Divergences of Sleep and Anesthesia

Sleep is a vital neurobiological process. Yet, despite its fundamental significance, delineating the endogenous neural pathways involved in sleep regulation has been slow to progress, due to a lack of diverse sleep models. Anesthesia, which has direct behavioral parallels to natural sleep, including a reversible loss of consciousness, decreased sensory awareness, and reduced behavioral responsiveness, is a natural choice to model specific components of sleep. Moreover, sleep and anesthesia are linked on both mechanistic and physiological levels. Animal research has demonstrated that anesthetic potency is modulated by sleep deprivation and sleep debt can be depleted by anesthetic interventions. Additionally, the archetypical electrophysiological dynamics of natural sleep, that is, the spontaneous alternations between activated and deactivated forebrain states, can be replicated using urethane anesthesia in rodent models. Increasingly, the overlaps and divergences between components of sleep and specific anesthetic agents are offering insight into the neurochemical mechanisms and fundamental brain circuitry involved in the induction and maintenance of unconsciousness.