Scientists Uncover Inner Workings of Rare Eye Cells

Three years ago, Brown University researchers discovered new eye cells – indeed a parallel visual system. Now, in a report in Nature, they explain how these exotic cells harness light energy to do their chief job: setting the body’s master circadian clock.
A Brown University team has found that a protein called melanopsin plays a key role in the inner workings of mysterious, spidery cells in the eye called intrinsically photosensitive retinal ganglion cells, or ipRGCs.
Melanopsin, they found, absorbs light and triggers a biochemical cascade that allows the cells to signal the brain about brightness. Through these signals, ipRGCs synchronize the body’s daily rhythms to the rising and setting of the sun. This circadian rhythm controls alertness, sleep, hormone production, body temperature and organ function.