Understanding the molecular mechanisms and the organizational logic of how synapses are constructed is essential to understanding neurotransmission in the brain. By knowing how connections form, when they form, and the rules they follow in comprising a circuit, we can understand how the brain processes information. By deciphering the genes involved in synapse formation and composition, we can also make great strides in understanding neurodevelopmental and intellectual disabilities. We combine genetics, state-of-the-art microscopy, biochemistry, and behavioral analysis to understand the links between molecules and function. For more information, visit www.moscalab.org.