How the Brain's Clock Gets Daily Enlightenment

CIRCADIAN CLOCKIn a burst of papers published in the past 2 months, culminating with two in this week's issue of Science (pp. [1065][1] and [1070][2]), researchers report their discovery of a new class of light-detecting retinal cells that send their signals to the brain's circadian clock; the cells also contain a molecule that may be the long-sought circadian photopigment. The papers, from five different labs, mesh seamlessly, clock researchers say. Indeed, the new work describes an entirely independent light-detection system in the mammalian eye. [1]: http://www.sciencemag.org/cgi/content/short/295/5557/1065 [2]: http://www.sciencemag.org/cgi/content/short/295/5557/1070