Finally, we confirmed the sufficiency of a transientmNgn2 pulse to induce neuronal activity. Again, we used the Axion MEA to compared neuronal activity of Ngn2-neurons with increasing lengths of doxycycline administration to induce mNgn2-induction (Fig. 6A). Using MEA, we compared the percentage of active electrodes and the percentage of wells showing bursting activity (Fig. 6B) of mNgn2-induced neurons with different lengths of doxycycline treatment. In two-week-old mNgn2-induced neurons, transient doxycycline addition for as little as two days increased the rate of neuronal activity relative to uninduced controls (Fig. 6B). Thus, transient mNgn2-induction seems to be sufficient to accelerate the maturation of functional neurons from NPCs.
