Fig. 3: The engulfment of synaptic inputs by OPCs is heightened by sensory experience and dampened by microglial depletion.

a, Schematic of the LDR visual deprivation and stimulation paradigm. b, Volumetric reconstructions of microglia (Iba1, white) and engulfed VGluT2⁺ inputs (magenta) in normally reared mice at P27 (control), mice dark-reared between P20 and P27 (LDR) and mice re-exposed to light for 10 h following LDR (LDR + 10). Scale bar, 2 μm. c, Quantification of the volume of synaptic material within microglia from each condition. One-way ANOVA (P > 0.05; NS, not significant); n (P27/LDR/LDR + 10): 28/49/64, from three mice per group. d, Reconstructions of OPCs (NG2, green) and engulfed synaptic inputs (VGluT2, magenta) from control, LDR, and LDR + 10 mice. Scale bar, 2 µm. e, Quantification of the volume of synaptic material contained within each OPC from control, LDR, and LDR + 10 mice. One-way ANOVA (P = 0.0199) with Tukey’s posthoc test; n (P27/LDR/LDR + 10): 20/30/42, from three mice per group. f, Reconstructions of OPCs (NG2, green) and engulfed TC inputs (VGluT2, magenta) in P27 mice following depletion of microglia using PLX5622 for 1 week. Scale bar, 2 μm. g, Quantification of the volume of synaptic material contained within each OPC in the presence or absence of microglia. Two-tailed Mann–Whitney t-test, P = 0.0082; n (control/PLX): 26/42, from three mice per group. h, Reconstructions of OPCs (NG2, green) and synaptic inputs (VGluT2, magenta) from LDR and LDR + 10 mice fed PLX5622 or control chow between P20 and P27. Scale bar, 2 μm. i, Quantification of synaptic engulfment in LDR and LDR + 10 mice containing or lacking microglia. Two-way ANOVA (stimulation: P < 0.0001; treatment: P < 0.05; interaction between stimulation and treatment: P < 0.05); n (OPCs, control/PLX): LDR = 45/52, LDR + 10 = 51/54, from three mice per group. In c,e,g, and i, individual data points are shown with bars representing mean ± s.e.m. *P < 0.05, **P < 0.01, ***P < 0.001 and ****P < 0.0001.