Retinal ganglion cells connect the nerve cells that process information in the eye with the visual centers of the brain. In the vertebrate retina, most retinal ganglion cells respond to light with either an increase in activity (ON-cells) or a decrease in activity (OFF-cells). In the mature retina, two features characterize the organization of the ON and OFF ganglion cells. First, the processes of ON and OFF cells ramify at different levels in the retina, and second, ON and OFF cells are distributed across the retina in regular mosaic patterns. The studies performed in this research program are directed at understanding the events underlying the formation of ON and OFF retinal pathways. Neuronal activity is known to play a role in the establishment and refinement of neural connections in a number of systems. In these investigations a series of experiments will be undertaken that are designed to assess the contribution of afferent input to stratification of dendritic arbors in the inner plexiform layer of the retina, and the role that axonal interactions at target nuclei play in programmed cell death and in defining dendritic territories in the retina. Precise and appropriate patterns of connections are necessary for the normal function of the nervous system. These studies will contribute in a fundamental way to our understanding of the strategies used in the development of these connections.
