Original recording from an acute experiment. Typical response to increasing the pentobarbital dose. Genioglossus and diaphragmatic electromyograms, respiratory flow, end-tidal carbon dioxide (CO2) concentration, and arterial blood-pressure during increasing doses of pentobarbital. With increasing pentobarbital concentrations, phasic genioglossus activity and CO2 increased, whereas diaphragmatic activity, respiratory rate, and respiratory flow decreased. MTA=moving time average, Dia=diaphragm.