Distinctive properties of cones in the retinal clock and the circadian system

Abstract The circadian system is a hierarchical network of cell and tissue-specific oscillators synchronized to the environmental light/dark cycle. Entrainment is mediated by the retina through diverse photosensitive cells and pigments. The retina is itself a complex circadian system whose cellular constitutive elements have not been fully characterized. By using the Nrl -/- cone gain-of-function mouse model we here show that the retinal network comprises an autonomous oscillator harbored in cones. We further provide novel evidence for an input from cones to the master clock, as revealed under constant light condition.