The functional profile was measured over the 3.5-week time period (Figure 2) and then repeated over a very wide maturation period (keeping the ratios of cells in each time period similar; Figure 3). The features measured in the short recording period were preserved over the longer recording period, almost as if they were keeping some special developmental program. Thus, for example, the NR sub-population had reduced sodium currents at 2 and 6 weeks after the start of differentiation. This larger data set allowed us to see more differences through the large biological noise, and strengthened the significance of some other differences. Again, we observed that NR neurons were hyperexcitable and were characterized by a wider, lower amplitude spike, with a more depolarized threshold for spiking and a higher amplitude fast AHP. The NR neurons had lower sodium currents at all stages of maturation. Their capacitance was larger than that of both the other groups (with a significant results compared with controls). LR neurons were hyperexcitable and were characterized by a narrower, higher amplitude spike and a higher amplitude fast AHP
