Neural circuits are information highways that connect diverse neuronal types and allow them to perform complex functions. The goal of my laboratory is to uncover the molecular and cellular mechanisms that regulate neural circuit formation, particularly in the visual and somatosensory systems. Zebrafish is a uniquely advantageous system for this endeavor. It is transparent, which allows continuous visualization of circuit development at high resolution. The small number of cells and compact size also make it a more tractable system to investigate how complex brain structures emerge in a vertebrate organism. We are also developing tools that would allow detailed mapping of neural circuits, e.g. Brainbow multi-color imaging and viral trans-synaptic tracing.