All human cell line work was performed on de-identified cell lines and approved by the Columbia University Institutional Review Board (IRB). IMR90 cl.4 hiPSCs (WiCell) (Yu et al., 2007 (link); Yu et al., 2009 (link); Chen et al., 2011 (link); Hu et al., 2011 (link)) were grown in StemFlex media (Thermo Scientific) on Cultrex (Biotechne) and passaged with ReLeSR as described previously (Song et al., 2021 ). Human neural progenitor cells (NPCs) were generated using dual SMAD inhibition as non-adherent embryoid bodies, followed by plating on polyornithine (10 ug/mL, Sigma P4957)/laminin (10 ug/mL, R&D Systems 3400-010-02) and subsequent manual rosette selection and expansion, as described previously (Topol et al., 2015 ; Sun et al., 2019 ). NPCs were maintained on Matrigel (Corning 354230) and split 1:2 to 1:3 at every 5–7 days. Neuronal differentiations were carried out by plating 200,000 cells/12 well-well or 500,000 cells/6 well-well in DMEM/F12 base media (Gibco 11320–033) supplemented with B27 (Gibco 17504–044), N2 (Gibco 17502–048), penicillin/streptomycin (Gibco 15140–122), BDNF (20 ng/mL, R&D Systems 248-BDB), and laminin (1 ug/mL). After 1 week of differentiation, AraC (Tocris 4520) was added at 100 nM to reduce remaining NPC proliferation. Neurons were differentiated for 6–11 weeks post NPC stage.