Fig. 1

Generation of iMNP and iMN in vitro. a Scheme of MNP and MN differentiation from human iPSCs using a small molecule cocktail. b Representative time-course images of iNEPs after six days of culture media conditions, iMNPs on day 12 under different conditions with RA and Pur, and a representative image of iMNs on day 18. A light microscopy image showing the iMature MNs on day 28 of differentiation. c Fluorescence image showing the expression of SOX1 in iNEP, OLIG2 in iMNP, co-localization of ChAT and HB9 in iMN, and SMI-32 in mature iMN. d Representative images of heatmap activity for plate-wide visualization of spike or beat rates and amplitudes on multi-electrode arrays (iPSCs, n = 3; iNEP, n = 3; iMN, n = 4; iMature MN, n = 4). e Measure of average spike numbers of active electrodes per well. f Measurement of the mean firing rate of active electrodes per well over 28 days of in vitro differentiation. Data are presented as mean ± SEM. Statistical significance was estimated using Kruskal–Wallis test with post hoc analysis and Mann–Whitney (†) test with least significant difference post hoc analysis (*); *, † P < 0.05, Scale bars = 50 μm. iNEP, iPSC-derived neuroepithelial progenitor cells; iMNP, iPSC-derived motor neuron progenitor cells; iMN, iPSC-derived motor neuron cells; iMature MNs, iPSC-derived mature motor neuron cells