Modern societies are experiencing an increasing trend of reduced sleep duration, with
nocturnal slee** time below the recommended ranges for health. Epidemiological and …

Humans live in a 24-hour environment, in which light and darkness follow a diurnal pattern.
Our circadian pacemaker, the suprachiasmatic nuclei (SCN) in the hypothalamus, is …

Seasonality patterns are reported in various psychiatric disorders. The current paper
summarizes findings on brain adaptations associated with seasonal changes, factors that …

Light is necessary for life, and artificial light improves visual performance and safety, but
there is an increasing concern of the potential health and environmental impacts of light …

Architectural lighting has potent biological effects but applied lighting practices that
capitalize on this potential have been limited. In this review, we endeavor to consolidate and …

Melatonin is a methoxyindole synthesized and secreted principally by the pineal gland at
night under normal light/dark conditions. The endogenous rhythm of secretion is generated …

Melatonin is an old and ubiquitous molecule in nature showing multiple mechanisms of
action and functions in practically every living organism. In mammals, pineal melatonin …

The electric light is one of the most important human inventions. Sleep and other daily
rhythms in physiology and behavior, however, evolved in the natural light-dark cycle [1], and …

Reduced exposure to daytime sunlight and increased exposure to electrical lighting at night
leads to late circadian and sleep timing [1–3]. We have previously shown that exposure to a …

The photopigment in the human eye that transduces light for circadian and neuroendocrine
regulation, is unknown. The aim of this study was to establish an action spectrum for light …