Ultradian Biological Periodicities in the Integration of Behavior

Abstract

Periodic phenomena in biology and behavior have been frequently observed, but their functional importance for the organism has not been the object of careful inquiry. This review paper presents the concept of an oscillator from a theoretical point of view, and applies this to high frequency, or “ultradian” biological rhythms. Integration of various physiological systems with behavioral processes in a maximally efficient way requires maximally efficient utilization of the available energy. Thus, optimal performance is accomplished as the many periodic phenomena become coordinated, or entrained, and is impossible without this high degree of integration of functions. The data concerning specific rhythms at the molecular, cellular, tissue, systemic, and behavioral levels are represented and a theoretical discussion of their mutual relationships and physiological significance is proposed. The role of the nervous system in optimizing the efficiency of the interaction of various biological and behavioral ultradian rhythms is emphasized.