We examined electrophysiological properties of neurons, selected for recording based on morphology (neurite projections and pyramidal-shaped soma), in iPS-derived neural cultures from one non-alcoholic subject, including the ability to generate action potentials and spontaneous synaptic activity. Cells that did not generate action potentials (7 of 58 cells examined) were excluded from further analysis. Consistent with reports on the developmental time course of hES cell-derived neural cells (Johnson et al., 2007), we observed that, after several weeks in culture, neurons developed resting membrane potentials of −50 to −60mV, and beginning at 10–12 weeks post-plating, iPS-derived neurons generated trains of action potentials in response to current injection (Figure 2A). Spontaneous synaptic activity with both fast and slow components typical of glutamatergic synaptic transmission was observed (Figure 2B).
