title: Re-examining "temporal niche".
abstract: The circadian system temporally organizes physiology and behavior throughout the 24-h day. At the core of this organization lies a network of multiple circadian oscillators located within the central nervous system as well as in virtually every peripheral organ. These oscillators define a 24-h temporal landscape of mutually interacting circadian rhythms that is known as the temporal niche of a species. This temporal niche is constituted by the collective phases of all biological rhythms emerging from this multi-oscillatory system. We review evidence showing that under different environmental conditions, this system can adopt different harmonic configurations. Thus, the classic chronobiological approach of searching for "the" circadian phase of an animal-typically by studying circadian rhythms of locomotor activity-represents a narrow look into the circadian system of an animal. We propose that the study of hormonal rhythms may lead to a more insightful assessment of a species' temporal niche.
authors.affiliation: Department of Biology and Program of Neurobiology and Behavior, University of Washington, Seattle, WA 98195, USA.
authors.forename: Benjamin L
authors.initials: BL
authors.lastname: Smarr
authors.forename: Michael D
authors.initials: MD
authors.lastname: Schwartz
authors.forename: Cheryl
authors.initials: C
authors.lastname: Wotus
authors.forename: Horacio O
authors.initials: HO
authors.lastname: de la Iglesia
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D056925:Circadian Rhythm Signaling Peptides and Proteins / Q000378:metabolism*; D004777:Environment; D005938:Glucocorticoids / Q000097:blood; D006728:Hormones / Q000378:metabolism*; D008550:Melatonin / Q000378:metabolism; D009043:Motor Activity / Q000502:physiology; D013045:Species Specificity; D013997:Time Factors
chemical_list: D056925:Circadian Rhythm Signaling Peptides and Proteins; D005938:Glucocorticoids; D006728:Hormones; D008550:Melatonin