Neuromodulation in developing motor microcircuits

•Neuromodulation confers flexibility upon locomotor network output.•Neuromodulators exert both acute and longer term effects on motor networks.•Neuromodulation configures neural networks during development.•Neuromodulatory mechanisms can be re-engaged in response to spinal injury.

Neuromodulation confers operational flexibility on motor network output and resulting behaviour. Furthermore, neuromodulators play crucial long-term roles in the assembly and maturational shaping of the same networks as they develop. Although previous studies have identified such modulator-dependent contributions to microcircuit ontogeny, some of the underlying mechanisms are only now being elucidated. Deciphering the role of neuromodulatory systems in motor network development has potentially important implications for post-lesional regenerative strategies in adults.