Development of ON and OFF Retinal Ganglion Cell Mosaics

Abstract

The regularity of cells in the vertebrate retina was first recognized in the mid-nineteenth century by Hannover (1843) who noted that “in many animals, double and single cones of the retina form a definite pattern.” Numerous investigators have since described the mosaics formed by cell populations in all three retinal nuclear layers (e.g., Wässle and Riemann, 1978; Young and Vaney, 1991; Cook and Becker, 1991; Hutsler and Chalupa, 1994). Such regular retinal arrays are thought to be necessary for the efficient functioning of the visual system. In particular, computer simulations and mathematical modeling have shown that the orderly distribution of photoreceptors is necessary for the adequate detection of spatial information (French et al., 1977). To preserve the integrity of such information, one would also expect complementary distributions in other retinal layers. Furthermore, as all visual information received by photoreceptors is conveyed to the brain via retinal ganglion cells (RGCs), these cells would be expected to possess a highly organized distribution pattern to ensure topographic input to visual target regions (Wässle and Riemann, 1978; Hirsch and Hylton, 1984). Moreover, as discussed by Jeremy Cook in this volume, it has een suggested that the presence of a regular distribution of cells is a determining factor for neuronal classification in the retina (Peichl, 1991; Wässle and Boycott, 1991).