I n mammals, photoreception is restricted to the eye. By contrast, nonmammalian vertebrates possess photoreceptors in a wide array of extraocular tissues, including the pineal complex and brain (1). The identity of the deep brain photoreceptors has remained elusive. They continue to be the least studied of all nonvisual photoreceptor classes, although their existence in the vertebrates has been...

A graded depolarization accompanied by nerve impulses can be recorded from the scorpion lateral and median eyes in response to light. Electron microscopy shows that axons forming the optic nerve arise directly from the photoreceptors. Thus, photoreceptors must respond both by the generation of a slow receptor potential and the initiation of spikes. The latency of the first spike, and the maxima...

The aim was to demonstrate functional properties of transplanted histologically normal photoreceptors. Subretinal intact-sheet transplants of fetal E17-E20 rat retinas to light-damaged albino rat eyes were fixed in light or dark, 2 to 42 weeks after transplantation, and stained immunohistochemically for certain phototransduction proteins. In light adapted transplants, transducin was predominant...

phyllopod (phyl) encodes a novel protein required for fate determination of photoreceptors R1, R6, and R7, the last three photoreceptors to be recruited into the ommatidia of the developing Drosophila eye. Genetic data suggests that phyl acts downstream of Ras1, raf, and yan to promote neuronal differentiation in this subset of photoreceptors. Ectopic expression of phyl in the cone cell precurs...