C3 and CD47 mediate sensory-motor circuit refinement during spinal cord development.

C3 and CD47 collaboratively eliminate supernumerary synapses in spinal circuits, ensuring proper motor development in mammals.

• Why it matters: Understanding how sensory-motor circuits are refined during development is crucial for addressing motor control disorders and neural wiring errors.
• What they did: Using mouse genetics, circuit mapping, electrophysiology, and behavioral analysis, the study identified supernumerary proprioceptive synapses that form and are later pruned via C3 and CD47 mechanisms.
• The result: The dual elimination system prevents miswired circuits, enabling mature motor function, and reveals a novel role for CD47 in spinal cord development distinct from its known brain functions.