Modeling the role of mid-wavelength cones in circadian responses to light

Neuron. 2007 Mar 1;53(5):677-87. doi: 10.1016/j.neuron.2007.02.005.


Nonvisual responses to light, such as photic entrainment of the circadian clock, involve intrinsically light-sensitive melanopsin-expressing ganglion cells as well as rod and cone photoreceptors. However, previous studies have been unable to demonstrate a specific contribution of cones in the photic control of circadian responses to light. Using a mouse model that specifically lacks mid-wavelength (MW) cones we show that these photoreceptors play a significant role in light entrainment and in phase shifting of the circadian oscillator. The contribution of MW cones is mainly observed for light exposures of short duration and toward the longer wavelength region of the spectrum, consistent with the known properties of this opsin. Modeling the contributions of the various photoreceptors stresses the importance of considering the particular spectral, temporal, and irradiance response domains of the photopigments when assessing their role and contribution in circadian responses to light.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Circadian Rhythm / physiology*
  • Circadian Rhythm / radiation effects
  • Gene Expression / physiology
  • Light*
  • Male
  • Mice
  • Mice, Knockout
  • Models, Biological
  • Motor Activity
  • Photoperiod
  • Retinal Cone Photoreceptor Cells / abnormalities*
  • Retinal Cone Photoreceptor Cells / physiology*
  • Retinal Ganglion Cells / physiology
  • Rod Opsins / genetics
  • Rod Opsins / physiology*
  • Thyroid Hormone Receptors beta / genetics


  • Rod Opsins
  • Thyroid Hormone Receptors beta
  • melanopsin