It has recently become apparent that rods and cones are not the only photoreceptors in mammals. A third class, known as intrinsically photosensitive retinal ganglion cells, use the photopigment melanopsin and mediate non-image-forming visual functions such as circadian photoentrainment. In teleost fish, a subset of horizontal cells is now shown to be photosensitive; the photopigment responsible for this seems to be melanopsin.
- Ning Cheng
- Takashi Tsunenari
- King-Wai Yau
