We seek to understand how neural networks are specified and how they assemble during development. The locomotor network of the Drosophila embryo and larva serves as a powerful experimental model. Composed of identified neurons whose connections have been reconstructed, we use genetics, imaging and electrophysiology to study fundamental questions about synapse development, dendritic growth and the regulation of plasticity. Current research topics include: Charting the developmental logic of neurotransmitters specification Determining how patterned growth during development leads to patterns of synaptic connections Activity dependent structural homeostasis and the maturation of network properties Reactive oxygen species seen in a different light, as newly identified regulators of synaptic growth Connectomics of memory circuits