Sleep is regulated by a homeostatic and a circadian process. Together these two processes
determine most aspects of sleep and related variables like sleepiness and alertness. The …

Organisms experience dramatic fluctuations in demands and stresses over the course of the
day. In order to maintain biological processes within physiological boundaries, mechanisms …

Mammalian circadian rhythms are controlled by endogenous biological oscillators, including
a master clock located in the hypothalamic suprachiasmatic nuclei (SCN). Since the period …

Environmental temperature cycles are a universal entraining cue for all circadian systems at
the organismal level with the exception of homeothermic vertebrates. We report here that …

The suprachiasmatic nucleus (SCN) is the primary circadian pacemaker in mammals.
Individual SCN neurons in dispersed culture can generate independent circadian …

Evidence is accumulating regarding the importance of circadian core oscillators, several
associated factors, and melatonin signaling in the maintenance of health. Dysfunction of …

Circadian rhythm disturbances are a common symptom among individuals with mood
disorders. The suprachiasmatic nucleus (SCN), in the ventral part of the anterior …

Wakefulness, non-rapid eye-movement (NREM) and rapid eye-movement (REM) sleep differ
from each other along three dimensions: behavioral, phenomenological, physiological …

Daily rhythms in behavior and physiology are programmed by a hierarchical collection of
biological clocks located throughout the brain and body, known as the circadian system …

Circadian clocks are endogenous oscillators driving daily rhythms in physiology and
behavior. Synchronization of these timers to environmental light–dark cycles ('entrainment') …