Neuronal Differentiation Inducer III selectively induces robust neuronal differentiation (Effective concentration = 20 μM) in various stem/progenitor cells. The underlying excitation-neurogenesis signaling is comprised of, at least in part, an initial NMDA receptor- and L-type channel-mediated Ca2+ influx, followed by an activation of CaMKII, phosphorylation/nuclear export of the MEF2 repressor HDAC5, the subsequent de-repression of MEF2, and the eventual activation of the HDAC-MEF2 epigenetic/transcriptional regulatory network.