Microglia phagocytose a subset of granule cell spines in the adult OB. (A–I) Representative illustrations (A, D, and G), SBF-SEM images (B, E, and H), and 3D reconstructions (C, F, and I) of microglia (n = 23 cells from three mice, pooled from eight independent experiments) in the process of “phagocytosis (early)” (A–C), “phagocytosis (late)” (D–F), or “partial phagocytosis (early)” (G–I). Blue arrows (A–I) indicate phagocytosed spines (A–C and G–I) or synaptic material (D–F). Yellow arrowheads (B) and circles (A, D, and G) indicate lysosomes and synaptic vesicles, respectively. Microglia (A–I, green), granule cells (A–C and G–I, pink), phagocytosed spine/synaptic material (B, C, E, F, H, and I, blue), and mitral cells (C, H, and I, light blue) are also shown. Pink arrows (C and I) indicate dendrodendritic synapses between granule cell spines and mitral cell dendrites. Interactive 3D models of microglial phagocytosis shown in A–C and G–I are shown at https://sketchfab.com/3d-models/phagocytosis-of-spine-by-microglia-7f168d4801e1444fb1f14750bbad7175 and https://sketchfab.com/3d-models/partial-phagocytosis-of-spine-by-microglia-b3b4332f1bc74dea86ae81965a3d23d3, respectively. (J) Event per microglial volume (density) of phagocytosis (early), phagocytosis (late), or partial phagocytosis (early) (n = 23 cells from three mice, pooled from eight independent experiments). Each dot indicates data from one cell. Scale bars in B, C, E, F, H, and I, 400 nm. Data shown are mean ± SEM.