is_about circadian sleep/wake cycle, non-REM sleep circadian sleep/wake cycle, sleep sleeping behavior circadian behavior non-rapid eye movement sleep behavior NREM sleep behavior George Gkoutos These stages are characterized by a slowing of brain waves and other physiological functions. behavior_ontology Behavior related to all sleep stages in the circadian sleep/wake cycle other than REM sleep. 2011-03-31T03:12:44Z