jsc2024e006094 (1/18/2024) --- Cross-section of a two-month old cerebral organoid observed under a fluorescence microscope. The colours obtained by immunofluorescence labeling highlight certain elements of the organoid’s structure. In blue the cell nuclei, in green, a sub-population of immature neurons, and in red, neurogenic zones with a high concentration of stem cells, in the shape of rosettes, where new neurons are forming. Credit: Institut Pasteur-SupBiotech.