Gross WL, et al. - Researchers examined how sedation influence specific cognitive systems using task-based functional magnetic resonance imaging. They made an assumption that deepening sedation would degrade semantic more than perceptual discrimination. Thirteen volunteers were examined for discrimination of pure tones and familiar names during wakefulness and propofol sedation targeted to light and deep sedation. Performed across sedation conditions, contrasts illustrated specific cognitive systems [auditory/motor (tones vs fixation), phonology (unfamiliar names vs tones), and semantics (familiar vs unfamiliar names)], and were followed by the region of interest analysis on representative regions. Results demonstrate that cognitive cortex shows broad impairment during sedation, with activation in primary sensory cortex beyond the loss of consciousness. In line with clinical experience, the findings suggest a dose-dependent decrease of higher cognitive functions during light sedation, despite partial preservation of sensory processes through deep sedation.