The focus of the lab is to understand social interactions in terms of neuronal function. How do animals solve the challenge of coordinating group behavior using their individual brains? As a model, we study young zebrafish which are innately social, optically transparent, and offer powerful genetic and molecular tools for monitoring and manipulating neurons. In many of our experiments, we use virtual reality to trick individual fish into fictive interactions and to measure the response to social signals in the brain via optical imaging. Using these tools, we define the neuronal cell types contributing to social behavior and how they function differently in individuals with extreme social behavior.