Topic: lampreys

The pupillary light response (PLR) controls pupil’s aperture according to the environmental luminosity, maximizing imaging efficiency while minimizing retinal damage. The PLR is present in most vertebrates, and two mechanisms have been described to achieve it: 1) In almost all vertebrate groups, it’s mediated by the Edinger–Westphal nucleus via the ciliary ganglion. 2) Some vertebrates, such as amphibia, fish, reptile and several mammals additionally show an iris-intrinsic mechanism evoked by the photoreceptor melanopsin, present in the sphincter pupillae muscle, whose activation produces musc