Self-renewing and pluripotency features of human pluripotent stem cells (hPSCs) have greatly facilitated understanding of the developing human nervous system and the pathogenesis of various neurological disorders (Mertens et al., 2016). Since the first report of neural rosette formation from human embryonic stem cells (ESCs) (Zhang et al., 2001), techniques to derive neural cells from hPSCs have continuously evolved, such that now we readily generate neural tissues in vitro, that resemble the 3-dimensional (3-D) organization of various brain regions (Kelava and Lancaster, 2016; Lancaster and Knoblich, 2014). Compared with monolayer cultures, 3-D neural tissues, named as brain organoids, provide unique opportunities to study neural development and to model neurological disorders (Quadrato et al., 2016). Recent studies identified human cell type-specific phenotypic changes during corticogenesis using brain organoid systems (Bershteyn et al., 2017; Li et al., 2017) and have studied the diversity of cell types generated during organoid development using large scale single cell analysis (Quadrato et al., 2017).
