formation of GABAergic synapses (Supplementary Fig. 6). Spontaneous and evoked IPSCs could be readily recorded at 5 and 7 WPI, but both frequency and amplitude of synaptic events were increased at least two-fold by 7 WPI, showing a progressive maturation of inhibitory synapses in AD-iN cells even after 5 WPI (Fig. 3c,d, and Supplementary Fig. 6). As expected, AD-iN cells cocultured with Ngn2-iN cells were also able to receive excitatory synaptic inputs from neighboring neurons (Fig. 3e).
