The release of neurotransmitters and hormones is an important step in the communication among neurons, as well as for a variety of other signaling mechanisms in our body. It is mediated by exocytosis, i.e. the fusion of storage vesicles, with the cellular membrane. We are interested in the cellular and molecular mechanisms, which control and trigger this process. Specializing on problems of synaptic short-term plasticity, on factors governing the availability of secretory vesicles, as well as on developmental aspects of synaptic transmission. An independent group, located at New York University, studies retinal ganglion cells in primates, in order to obtain insight into higher aspects of signal processing in the visual system, particularly with respect to color vision.