Ketamine is a unique anesthetic agent that induces dissociative anesthesia, characterized by perceptual detachment, analgesia, and altered states of consciousness. Beyond its widespread use in anesthesia, subhypnotic ketamine dosing has emerged as a rapid-acting antidepressant and a valuable model for probing the neural mechanisms underlying consciousness and neuropsychiatric disorders. At the...
During wakefulness, external stimuli elicit conscious experiences. In contrast, dreams and drug-induced dissociated states are characterized by vivid internally generated conscious experiences and reduced ability to perceive external stimuli. Understanding the physiological distinctions between normal wakefulness and dissociated states may therefore disambiguate signatures of responsiveness to...
The relationship between sensory stimuli and perceptions is brain-state dependent: in wakefulness, suprathreshold stimuli evoke perceptions; under anesthesia, perceptions are abolished; and during dreaming and in dissociated states, percepts are internally generated. Here, we exploit this state dependence to identify brain activity associated with internally generated or stimulus-evoked...