Circadian and light modulation of behavior

Cara M. Altimus, Tara A. LeGates, Samer Hattar

Research output: Chapter in Book/Report/Conference proceedingChapter


Nearly all organisms contain a circadian biological clock that is responsible for coordinating the temporal functions of many physiological systems. The circadian clock is synchronized to the earth's day/night rhythms via changes in the intensity of light throughout the cycle. In mammals, the eyes and specifically the intrinsically photosensitive retinal ganglion cells are essential for transmitting light information to the brain to influence the physiology of the organism. Several biochemical, hormonal, molecular, and behavioral functions are affected by the interaction of the circadian clock with the daily light/dark cycle. Furthermore, many studies have shown an association between circadian biology and mood regulation. Here, we present several behavioral methods in mice and humans for the measurement of the interaction between the endogenous biological clock and light. By incorporating circadian phenomena into mood studies, the link between the clock, light, and mood could be better understood. Further, modification of the light/dark environment should provide tools to control sleep, mood, and cognition via direct light input on behaviors.

Original languageEnglish (US)
Title of host publicationMood and Anxiety Related Phenotypes in Mice
Subtitle of host publicationCharacterization Using Behavioral Tests
PublisherHumana Press
Number of pages19
ISBN (Print)9781607613022
StatePublished - 2009

Publication series

ISSN (Print)0893-2336
ISSN (Electronic)1940-6045


  • Biological clock
  • Bipolar disorder
  • Circadian rhythm
  • Depression
  • Light
  • Mice
  • Mood
  • Seasonal affective disorder

ASJC Scopus subject areas

  • General Neuroscience
  • General Biochemistry, Genetics and Molecular Biology
  • Pharmacology, Toxicology and Pharmaceutics(all)
  • Psychiatry and Mental health


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