Functional analyses of iN cells were conducted using whole-cell patch-clamp electrophysiology as described elsewhere (Oni et al., 2016; Yang et al., 2017; Halikere et al., 2019). For current-clamp recordings, a K-gluconate internal solution was used, which consisted of (in mM): 126 K-gluconate, 4 KCl, 10 HEPES, 0.05 EGTA, 4 ATP-magnesium, 0.3 GTP-sodium, and 10 phosphocreatine. For voltage-clamp recordings, a Cs2+-based solution was used, which consisted of (in mM): 40 CsCl, 3.5 KCl, 10 HEPES, 0.05 EGTA, 90 K-gluconate, 1.8 NaCl, 1.7 MgCl2, 2 ATP-magnesium, 0.4 GTP-sodium, and 10 phosphocreatine. The pH was adjusted to 7.2 with KOH for the solution for the current-clamp recordings and with CsOH for the solution for the voltage-clamp recordings, and osmolarity was adjusted to 270–290 mOsm. The bath solution consisted of (in mM): 140 NaCl, 5 KCl, 2 CaCl2, 2 MgCl2, 10 HEPES, and 10 glucose. The pH was adjusted to 7.4 with NaOH. Spontaneous inhibitory postsynaptic currents (sIPSCs) were recorded at a holding potential of −70 mV in the presence of 20 μM CNQX (Tocris, catalog# 0190) added to the perfusion solution. Miniature inhibitory
