Fig. 1. Approaches for organoid ge-neration. Unguided approach: Orga-noids are developed based on self-organization principles of stem-cell aggregates resulting in cerebral orga-noids. Cerebral organoids contain heterogeneous population of tissues resembling various embryonic brain vesicles (middle panel). Guided approach: Stem-cell aggregates can be directed to distinct cell fates resulting in region-specific brain organoids in the presence of external patterning cues.