The goal of our research is to create human induced pluripotent stem cell (hiPSC) neural differentiation models for studying the cellular and molecular basis of human neural development and pathogenesis of neurodevelopmental disease, and to develop stem cell regenerative medicine to treat neurological disorders. We have been developing hiPSC-based in vitro 2-dimensional (2D) neural differentiation and 3D CNS organoid models and in vivo human chimeric mouse brain models to investigate how abnormal gene expression in neurodevelopmental disorders, such as Down syndrome, causes abnormal brain development, changes synaptic plasticity, and leads to cognitive deficits in these disorders. In addition, hiPSCs hold great promise for developing cell therapies to replace damaged brain cells and restore brain functions after CNS injury. We also study how to derive functionally competent neural cells from hiPSCs for neural repair. The basic and translational stem cell research we are pursuing critically bridges between the understanding of human neural development in heath and disease, and the development of stem cell medicine to treat neurological disorders.