The Neurobiology of Circadian Rhythms

Psychiatr Clin North Am. 2015 Dec;38(4):645-65. doi: 10.1016/j.psc.2015.07.003. Epub 2015 Sep 5.


There is a growing recognition that the coordinated timing of behavioral, physiologic, and metabolic circadian rhythms is a requirement for a healthy body and mind. In mammals, the primary circadian oscillator is the hypothalamic suprachiasmatic nucleus (SCN), which is responsible for circadian coordination throughout the organism. Temporal homeostasis is recognized as a complex interplay between rhythmic clock gene expression in brain regions outside the SCN and in peripheral organs. Abnormalities in this intricate circadian orchestration may alter sleep patterns and contribute to the pathophysiology of affective disorders.

Keywords: Biological rhythms; Circadian oscillator; Clock; Intrinsically photosensitive retinal ganglion cells; Suprachiasmatic nucleus.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Animals
  • Circadian Clocks / genetics
  • Circadian Clocks / physiology
  • Circadian Rhythm / genetics
  • Circadian Rhythm / physiology*
  • Humans
  • Neural Pathways / physiology*
  • Retinal Ganglion Cells / physiology*
  • Serotonergic Neurons / physiology
  • Suprachiasmatic Nucleus / physiology*