differentiation to O4+‐oligodendrocytes is associated with a reduced degree of outward rectification (Fig. 2B). Rectification indices were subsequently calculated (see Materials and Methods section) to quantify such rectification shifts and revealed that current rectification was reduced in each line of week 3 O4+‐oligodendrocytes when compared with the levels seen in PDGFRα+‐OPCs (ESC, 13.4 ± 2.2%; iPS1, 11.8 ± 3.8%; iPS2, 12.6 ± 2.5%, Fig. 2C). A reduction in input resistance also accompanies this shift in membrane current properties (Fig. 2D) therefore providing added support to the notion that changes in ion channel expression accompany oligodendrocyte differentiation from hPSC‐derived OPCs. Furthermore, whole‐cell capacitance measurements are consistent that the membrane compartment increases in size during the oligogodendrocyte differentiation process (Fig. 2E). Together these data indicate that maturation is active in differentiated oligodendrocytes.
