ipRGC; Intrinsically photosensitive Retinal Ganglion Cells (ipRGCs), = photosensitive Retinal Ganglion Cells (pRGC)= melanopsin-containing retinal ganglion cells. While responses to light in mice lacking rods and cone cells were first noted in 1923, they were forgotten, then rediscovered in the early 1990s. Excited by light even when all influences from photoreceptors (rods and cones) are blocked (pharmacological agents or dissociation from retina). Optothalamic tract to NSC
