Reconstructed three-dimensional image of a human cerebral organoid, including a network of ventricle structures. Arrowheads point to choroid plexus. Reprinted with permission from Renner M, Lancaster MA, Bian S, Choi H, Ku T, Peer A, Chung K, Knoblich JA. EMBO J [Internet]. 2017 May 15; 36(10):1316-1329. Copyright 2017; John Wiley & Sons.