%0 Journal Article %T 3D reconstruction of the cerebellar germinal layer reveals tunneling connections between developing granule cells %+ Trafic membranaire et Pathogénèse - Membrane Traffic and Pathogenesis %+ Université Paris-Saclay %+ Icahn School of Medicine at Mount Sinai [New York] (MSSM) %+ Universidad de Ingeniería y Tecnología [Lima, Peru] (UTEC) %+ Harvard University %A Cordero Cervantes, Diégo %A Khare, Harshavardhan %A Wilson, Alyssa Michelle %A Mendoza, Nathaly Dongo %A Coulon-Mahdi, Orfane %A Lichtman, Jeff William %A Zurzolo, Chiara %Z To C.Z.: Inception program (Investissement d’Avenir grant) ANR-16-CONV-0005, ANR-17-CONV-0005 Projet Q-life, Cancéropôle Ile-de-France 2018-1-PL BIO-03-IP-1, Big Brain Theory Program cofunded by Institut Pasteur and Paris Brain Institute, SRA3-SPAIS seed grant from Institut Pasteur Paris, and Equipe FRM - EQU202103012630; to J.W.L.: U19 NS104653, U24 NS109102-01, and P50MH094271 Conte Center; C.Z. was supported by the Radcliffe Institute for advanced study at Harvard (fellowship program 2018-2019). D.C.C. was supported by the PPU program at IP. %< avec comité de lecture %@ 2375-2548 %J Science Advances %I American Association for the Advancement of Science (AAAS) %V 9 %N 14 %P eadf347 %8 2023-04-05 %D 2023 %R 10.1126/sciadv.adf3471 %M 37018410 %Z Life Sciences [q-bio]/Cellular BiologyJournal articles %X The difficulty of retrieving high-resolution, in vivo evidence of the proliferative and migratory processes occurring in neural germinal zones has limited our understanding of neurodevelopmental mechanisms. Here, we used a connectomic approach using a high-resolution, serial-sectioning scanning electron microscopy volume to investigate the laminar cytoarchitecture of the transient external granular layer (EGL) of the developing cerebellum, where granule cells coordinate a series of mitotic and migratory events. By integrating image segmentation, three-dimensional reconstruction, and deep-learning approaches, we found and characterized anatomically complex intercellular connections bridging pairs of cerebellar granule cells throughout the EGL. Connected cells were either mitotic, migratory, or transitioning between these two cell stages, displaying a chronological continuum of proliferative and migratory events never previously observed in vivo at this resolution. This unprecedented ultrastructural characterization poses intriguing hypotheses about intercellular connectivity between developing progenitors and its possible role in the development of the central nervous system. %G English %2 https://pasteur.hal.science/pasteur-04065869v2/document %2 https://pasteur.hal.science/pasteur-04065869v2/file/sciadv.adf3471.pdf %L pasteur-04065869 %U https://pasteur.hal.science/pasteur-04065869 %~ CNRS %~ UNIVERSITE-PARIS %~ ANR %~ FRM %~ UMR3691