Ultradian Rhythms in Behavior:
Ultradian rhythms (URs) are evident at every level of biological organization. Across diverse taxa, URs in feeding behavior, locomotor activity, cognitive function, body temperature, hormone secretion and sleep impose temporal order at multiple levels of biological organization, yet little is known about the neuroendocrine substrates that generate and entrain URs in behavior. In collaboration with colleagues at U.C. Berkeley, we are investigating how URs change across the day and the year, how they differ between the sexes, and how hormones and non-photic cues influence their generation and expression.
Recent published work from our collective has identified:
URs are enhanced during pregnancy and lactation in female Syrian hamsters. [PubMed]
The circadian clock exerts a strong influence on URs, but URs can persist independent of a functional SCN. [PubMed]
Seasonal changes in day length markedly alter the UR waveform. [PubMed]
URs are relatively uninfluenced by changes in gonadal hormone secretion [PubMed]
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