How the brain transforms information from the complex acoustic waves of natural sounds into the sound perceptions that we experience is still a mystery. We have systematically sampled the neural representations of sounds across the auditory system and identified key transformations of the information which we think are necessary to build identifiable auditory objects that can be associated to behavioral responses. This exquisite processing of sound information is profoundly disrupted by anesthesia, as early as in the first relay of the auditory system but remains intact in sleep up to the auditory cortex, the most central structure dedicated to sound processing. Thus, contrary to what is still often assumed, sleep permits the detailed recognition of sounds. These results also highlight the profound difference in perceptual awareness states produced by sleep and anesthesia. In this talk, I will also highlight a novel acousto-optic technology for ultrafast all optical imaging.