Fig. 6: Functional analysis of RGC-iNs.

Day 14 (D14) RGC-iNs stained with a DAPI, TAU, and MAP2. b DAPI and TUJ1 overlayed with tdTomato. c Patched D14 RGC-iN. d Electrophysiological recordings from RGC-iNs under current clamp showing single action potentials elicited in response to depolarizing current injection as early as 14 days. By day 28, RGC-iNs are shown to exhibit repetitive action potentials. Resting membrane potential = −60 mV. Threshold current = 60 pA. e Under voltage clamp, depolarizing voltage steps in RGC-iNs reveal both fast inward Na+ and outward K+ currents, which are increased at day 28 compared to day 14. f, left: An example AMPA puff (1 mM) evoked current in a voltage-clamped RGC-iN. f, right: I–V plot for AMPA puff evoked currents in RGC-iN (solid symbols), and linear fit (solid line). Traces on the left show time course and double exponential fit to putative sEPSCs. g Example of current traces showing spontaneous excitatory post-synaptic currents (sEPSCs) that were blocked by the AMPA/Kainate antagonist DNQX. Scale a, b = 200 µm.