A model of phototransduction by the human circadian system

Brain Res Brain Res Rev. 2005 Dec 15;50(2):213-28. doi: 10.1016/j.brainresrev.2005.07.002. Epub 2005 Oct 7.


The absolute and spectral sensitivities to light by the human circadian system, measured through melatonin suppression or phase shifting response, are beginning to emerge after a quarter century of active research. The present paper outlines a hypothesized model of human circadian phototransduction that is consistent with the known neuroanatomy and physiology of the human visual and circadian systems. Spectral opponency is fundamental to the model, providing a parsimonious explanation of some recently published data. The proposed model offers a framework for hypothesis testing and subsequent discussion of the practical aspects of architectural lighting with respect to light and health.

Publication types

  • Review

MeSH terms

  • Animals
  • Circadian Rhythm / physiology*
  • Electrophysiology
  • Humans
  • Light
  • Light Signal Transduction / physiology*
  • Melatonin / metabolism
  • Models, Biological*
  • Neuroanatomy


  • Melatonin