Patterns of Spinal Sensory-Motor Connectivity Prescribed by a Dorsoventral Positional Template

SummarySensory-motor circuits in the spinal cord are constructed with a fine specificity that coordinates motor behavior, but the mechanisms that direct sensory connections with their motor neuron partners remain unclear. The dorsoventral settling position of motor pools in the spinal cord is known to match the distal-to-proximal position of their muscle targets in the limb, but the significance of invariant motor neuron positioning is unknown. An analysis of sensory-motor connectivity patterns in FoxP1 mutant mice, where motor neuron position has been scrambled, shows that the final pattern of sensory-motor connections is initiated by the projection of sensory axons to discrete dorsoventral domains of the spinal cord without regard for motor neuron subtype or, indeed, the presence of motor neurons. By implication, the clustering and dorsoventral settling position of motor neuron pools serve as a determinant of the pattern of sensory input specificity and thus motor coordination.PaperClip To listen to this audio, enable JavaScript on your browser. However, you can download and play the audio by clicking on the icon belowHelp with MP3 filesOptionsDownload audio (3757 K)

Graphical AbstractFigure optionsDownload high-quality image (246 K)Download as PowerPoint slideHighlights
► Dorsoventral cues provide a template for spinal sensory-motor connectivity
► Sensory axons project to dorsoventral tiers independently of motor neurons
► Sensory tier targeting provides a purpose for precise motor neuron positioning
► Columelar organization facilitates sensory innervation of synergistic motor pools