Mechanisms controlling the formation of retinal mosaics

Most regions of the nervous system derive their power of processing from a modular architecture. The retina is an outstanding example of modular circuit design. Retinal neurons are stacked in layers and within each layer neurons of the same type commonly form orderly arrays, or mosaics. Here we review current knowledge on the mechanisms of retinal mosaic formation, and discuss the hypothesis that retinal mosaics are the building blocks in the assembly of retinal circuitry.