Details:
The series of molecular signals initiated by binding of a ligand to the transmembrane receptor smoothened in a precursor cell in the spinal cord that contributes to the process of a precursor cell becoming capable of differentiating autonomously into a motor neuron in an environment that is neutral with respect to the developmental pathway. [GO_REF:0000021, GOC:cls, GOC:dgh, GOC:dph, GOC:jid, GOC:mtg_15jun06, PMID:15936325]