Abstract: Generating neurons from human induced pluripotent stem cells (hiPSCs) overcomes the limited access to human brain tissues and greatly facilitates the research in neuroscience (Karagiannis et al., 2019). However, it is still a big challenge to obtain a particular neuronal subtype with high purity and yield to conduct certain studies, such as determining the pathogenesis of diseased neurons using biochemical approaches. Motor neurons (MNs) are a specialized neuronal subtype responsible for innervating musculature in the periphery and governing both autonomic and volitional movements. Dysfunctions in MNs are implicated in a variety of movement diseases, such as amyotrophic lateral sclerosis (ALS), progressive muscular atrophy, and dystonia (Sances et al., 2016; Ding et al., 2020b). ALS belongs to MN diseases, which are caused by gradual degeneration and death of MNs in the brain (upper MNs) and/or in the spinal cord (lower MNs). Several pathogenic mechanisms are involved in ALS, including glutamate excitotoxicity, dysregulated interactions between neurons and glial cells, intracytoplasmic and intranuclear aggregation of certain proteins and RNAs, impaired nucleocytoplasmic transport, and changes in the axon terminals and neuromuscular junctions (NMJs) (Sances et al., 2016). So far, there are no specific treatments available to cure these diseases due to unclear pathophysiological mechanisms. Generation of patient-specific MNs will provide valuable in vitro model systems in deciphering the pathogenesis of these diseases. Recently, we have developed an approach by which functional MNs could be generated from hiPSCs via lentiviral delivery of three transcription factors (Figure 1). These MNs robustly expressed generic neuronal markers, MN-specific markers, and showed electrical maturation and firing of action potentials within 3 weeks (Sepehrimanesh and Ding, 2020). Compared to previous methods (Tang et al., 2017), this approach significantly improved the neuronal survival, purity, and yield, making it feasible to obtain abundant patient-specific MNs for biochemical studies in modeling movement diseases.