iPSCs were differentiated into neural cell cultures as previously described (Lieberman et al. 2012) using an established protocol developed by the WiCell Institute for the differentiation of human embryonic stem cells into neural cells of a forebrain lineage (#SOP-CH-207, REV A, www.wicell.org, Madison, WI). In the absence of specific neuronal lineage morphogens the protocol results in forebrain neurons containing both glutamatergic and GABAergic neurons in an approximately 3:1 ratio as well as astrocytes (Fink et al., 2017). Mature neurons contain focal clusters of synaptic proteins and exhibit spontaneous excitatory and inhibitory currents. Briefly, we used an “Embryoid Body” (EB)-based protocol wherein iPSC colonies are removed from the feeder layer substrate and cultured in suspension before going through a neural induction phase to generate primitive neuroepithelial cells. Following 3 weeks of culture in neural induction media containing 1x N2 supplement and 2 μg/mL heparin (Sigma-Aldrich), cells were dissociated and cultured in 24-well plates on 0.1mg/mL polyornithine and Matrigel (BD Biosciences, Bedford, MA) coated glass coverslips in neural differentiation media containing the neural growth factors 1x B27 supplement (Thermo Fisher Scientific), 1μg/mL
