Suprachiasmatic nucleus: cell autonomy and network properties

Annu Rev Physiol. 2010:72:551-77. doi: 10.1146/annurev-physiol-021909-135919.


The suprachiasmatic nucleus (SCN) is the primary circadian pacemaker in mammals. Individual SCN neurons in dispersed culture can generate independent circadian oscillations of clock gene expression and neuronal firing. However, SCN rhythmicity depends on sufficient membrane depolarization and levels of intracellular calcium and cAMP. In the intact SCN, cellular oscillations are synchronized and reinforced by rhythmic synaptic input from other cells, resulting in a reproducible topographic pattern of distinct phases and amplitudes specified by SCN circuit organization. The SCN network synchronizes its component cellular oscillators, reinforces their oscillations, responds to light input by altering their phase distribution, increases their robustness to genetic perturbations, and enhances their precision. Thus, even though individual SCN neurons can be cell-autonomous circadian oscillators, neuronal network properties are integral to normal function of the SCN.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Animals
  • Biological Clocks / physiology
  • Circadian Rhythm / physiology*
  • Drosophila
  • Hormones / physiology
  • Humans
  • Light
  • Nerve Net / anatomy & histology
  • Nerve Net / cytology*
  • Nerve Net / physiology*
  • Neurons / physiology*
  • Photoperiod
  • Suprachiasmatic Nucleus / anatomy & histology
  • Suprachiasmatic Nucleus / chemistry*
  • Suprachiasmatic Nucleus / physiology*


  • Hormones