Spiking activity is observed in the majority of cells when OPCs are depolarized and is blocked by Na V‐channel blocker TTX. However, these spikes are not classified as bone fide action potentials due to their low amplitude. Oligodendrocytes did not exhibit any spiking activity, and we found that the functional expression of Na V channels to be largely restricted to OPCs in agreement with reports from rodent oligodendroglial cells 24, 25, 51. In contrast to our data, hPSC‐derived OPCs have been previously shown to exhibit regenerative action potential firing in response to depolarization 52, however no native TTX‐sensitive current has been observed in in vitro murine PSC‐derived OPCs 48. It is important to highlight that numerous reports describe native OPCs being heterogeneous in their ability to display either spiking or nonspiking behaviors, which are likely to represent the differentiation/maturation status of the OPC rather than developmentally independent subclasses of OPC 26, 27, 28, 53. Since OPCs in this study are examined after a period of 1 week in oligodendrocyte differentiation medium, it may be argued that the early processes of
