Genetic and physiological characterization of motor circuits

Our long-term goal is to use genetic markers to identify neurons that regulate motor functions and transgenic mouse models to understand their contribution to the rhythmic motor output. We have identified a class of excitatory neurons located in the brainstem reticular formation and the ventral spinal cord that express homeodomain factor Chx10. Genetic ablation of these neurons in mice has revealed two distinct functions. Chx10 neurons in the brainstem regulate the frequency and stability of the respiratory rhythm generated in the Pre-Bötzinger complex (PBC). Chx10 neurons in the spinal cord regulate the locomotor network activity. Physiological and anatomical analysis of Chx10 neurons in the spinal cord of transgenic mice has revealed novel insight into the organization of locomotor networks.