FIGURE 3.

Excitability and electrical properties of hiPSC-derived RGC-like cells after differentiation in 2D. (A) Top, infrared image of a recording electrode in contact with a RGC 3 weeks after plating of retinal cells derived from D56 organoid Scale bar, 20 μm. Bottom, example of an extracellular recording from the same cell displaying spontaneous firing activity (0.31 ± 0.07 Hz; mean ± SEM; N = 9; n = 20 out of 61 recorded cells). (B) Whole-cell patch-clamp recording of a representative cell in voltage-clamp mode. Current responses to voltage steps are obtained by stepping the membrane potential from –100 to +40 mV in 10 mV increments. Note the presence of fast inward currents (arrow head); (N = 5; n = 15 out of 22 recorded cells). (C) Whole-cell patch-clamp recording in current-clamp mode. Injecting positive current (40 pA) in the cell (blue bars) leads to firing activity (N = 5; n = 7 out of 10 recorded cells). (D) Recording in one cell of a long inward current evoked by glutamic acid (1 mM) application and compatible with a synaptic current; this response has been reproduced three times.