Based on genetic and biochemical advances on the molecular mechanism of circadian rhythms, a computational model for the mammalian circadian clock is used to examine the dynamical bases of circadian-clock-related physiological disorders in humans. Entrainment by the light-dark cycle with a phase advance or a phase delay is associated with the Familial advanced sleep phase syndrome (FASPS) or th...

A diurnal rhythm of eating-fasting promotes health, but the eating pattern of humans is rarely assessed. Using a mobile app, we monitored ingestion events in healthy adults with no shift-work for several days. Most subjects ate frequently and erratically throughout wakeful hours, and overnight fasting duration paralleled time in bed. There was a bias toward eating late, with an estimated <25% o...

Circadian clocks regulate daily fluctuations of many physiological and behavioral aspects in life. They are synchronized with the environment via light or temperature cycles [1]. Natural fluctuations of the day length (photoperiod) and temperature necessitate a daily reset of the circadian clock on the molecular level. In Drosophila, the blue-light photoreceptor Cryptochrome (Cry) mediates a ra...

The suprachiasmatic nucleus (SCN) is the neuroanatomical locus of the mammalian circadian pacemaker. Here we demonstrate that an abrupt shift in the light/dark (LD) cycle disrupts the synchronous oscillation of circadian components in the rat SCN. The phases of the RNA cycles of the period genes Per1 and Per2 and the cryptochrome gene Cry1 shifted rapidly in the ventrolateral, photoreceptive re...

The mammalian genome encodes at least a dozen of genes directly involved in the regulation of the feedback loops constituting the circadian clock. The circadian system is built up on a multitude of oscillators organized according to a hierarchical model in which neurons of the suprachiasmatic nuclei of the hypothalamus may drive the central circadian clock and all the other somatic cells may po...

BACKGROUND The rapid deployment of Army aviation personnel across time zones, combined with missions beginning immediately upon arrival, results in desynchronization of physiological and cognitive performance rhythms. Implementation of effective countermeasures enhances safety, health, well-being, and mission completion. The naturally occurring hormone melatonin has been suggested as an effecti...

SeaWinds data are provided by the Jet Propulsion Laboratory (JPL) at 25-km resolution, whereas most numerical weather prediction (NWP) models use observations at least a 100-km density. We have developed a QuikSCAT wind product at a coarser resolution than the JPL product in order to achieve a more appropriate information content for assimilation in NWP models. This product includes quality con...

The robustness and limited plasticity of the master circadian clock in the suprachiasmatic nucleus (SCN) is attributed to strong intercellular communication among its constituent neurons. However, factors that specify this characteristic feature of the SCN are unknown. Here, we identified Lhx1 as a regulator of SCN coupling. A phase-shifting light pulse causes acute reduction in Lhx1 expression...

BACKGROUND Circadian rhythms govern many aspects of physiology and behavior including cognitive processes. Components of neural circuits involved in learning and memory, e.g., the amygdala and the hippocampus, exhibit circadian rhythms in gene expression and signaling pathways. The functional significance of these rhythms is still not understood. In the present study, we sought to determine the...