Communication in the nervous system is mediated by chemical, electrical and ephaptic transmission. Electrical and ephaptic communication through gap junctions or gap junction hemichannels is far less understood than chemical transmission, but accruing evidence suggests a significant contribution in health and disease conditions like epilepsy, ischemia or cancer. In my research, I address the functional role of electrical and ephaptic communication in the vertebrate visual system starting from characterization of genes encoding gap junction type proteins in vitro to the development of animal models for functional analysis in vivo. The ultimate goal of my research is to answer the question of how these communication pathways contribute and interact to form a functional nervous system.