Caenorhabditis elegans is a free-living microscopic roundworm. Its nervous system is small and only contains a few hundred cells. Despite this anatomical simplicity, the C. elegans nervous system displays genetic and neurochemical complexity that rivals that of much larger nervous systems. Importantly, stereotyped behaviors are generated by specific circuits and the neurotransmitter signaling systems they use. Genetic studies of these behaviors can identify molecules required for critical modes of neurochemical signaling, for example signaling by serotonin, dopamine, and neuropeptides. Understanding the molecular underpinnings of these signaling systems will advance the development of new psychopharmacology for the treatment of a host psychiatric and neurological diseases.
Our studies of neurochemical signaling have led us to also study the development of neural circuits that use neuropeptides to control behavior. As the nervous system develops, neurons acquire remarkable and highly specialized physiology. Many neurodevelopmental disorders are caused by defects in this process, which motivates our interest in understanding the molecular mechanisms that generate specialized neuron-types during development. As models for the study of neural development, we have selected a set of sensory neurons that detect respiratory gases and release neuropeptides to control behavior.