This paper reviews lateralized ultradian rhythms in the nervous system and their unique place in evolutionary development. The rhythmic lateralization of neural activity in paired internal structures and the two sides of the central and autonomic nervous system is discussed as a new view for the temporal and spatial organization of higher vertebrates. These lateralized neural rhythms are integral to the hypothesis of the basic rest-activity cycle. Rhythms of alternating cerebral hemispheric dominance are postulated to be coupled to oscillations of the ergotrophic and trophotrophic states. The nasal cycle is coupled to this cerebral rhythm. This lateralized central and autonomic rhythm is discussed in relationship to ultradian rhythms of neuroendocrine activity, REM and NREM sleep, lateralized rhythms of plasma catecholamines, and other lateralized neural events. The relationship of this phenomenon to stress and adaptation is postulated. The effects of unilateral forced nostril breathing is reviewed as a method to alter cerebral activity, cognition, and other autonomic dependent phenomena.