Identification of a spinal circuit for skilled locomotion

Neural circuits in the spinal cord have a critical role in integrating sensory information and descending commands to coordinate body movements. Defining the functional diversity of spinal neurons is therefore essential for understanding the mechanisms underlying motor control. In this study, by combining anatomical, molecular, and functional analyses in mice, we identified and characterized a subtype of ascending spinal neurons belonging to the V0g family. We found that V0g ascending neurons are integrated in lumbar sensorimotor circuits and their function is specifically required for the execution of precise limb movements necessary for skilled locomotion. This work advances our understanding of the functional organization of V0 neurons and highlights a previously unappreciated role in adjusting body movements to the more demanding needs of skilled locomotor tasks Rabies retrograde tracing was used to label with a fluorecent protein the nuclei of ascending and descending mouse spinal neurons reciprocally connecting the lumbar and cervical enlargements. Nuclei were isolated via fluorescence-activated nucleus sorting and analysed using sn-RNA-seq.