Forced turnover of microglia attenuated deficits in neuronal connectivity 30 dpi. A, Adult male C57BL/6 mice were subjected to mFPI (TBI) or left as uninjured controls (CON). At 7 dpi, mice were provided diets formulated with either vehicle or a CSF1R antagonist (PLX5622) for 7 d and then returned to their standard rodent chow at 14 dpi. At 30 dpi (16 d of microglia repopulation), mice were killed, and tissues were collected for analysis of dendritic spines, MBP, or CAPs. B, Representative cortical images of DiI⁺ dendrites 30 dpi from each treatment group are shown (n = 6). Bar graphs represent (C) dendritic spine volume, (D) dendritic spine area, and (E) dendritic spine density. F, CAPs were stimulated and measured from ex vivo preparation of the corpus callosum (n = 4) and representative N1 and N2 tracings of CAP from control and TB1 mice 30 dpi are shown. Graphs represent average recording amplitude across a range of stimulus intensities for (G) N1 and (H) N2. AUC determined for the (I) N1 and J) N2 amplitudes. K, Representative cortical images of MBP⁺ labeling 30 dpi from each treatment group (n = 6). L, Percent MBP⁺ labeling in cortical sections. Graphs represent mean ± SEM. Means with * are significantly different from CON-Veh (p < 0.05) and means with † are significantly different from both CON-Veh and PLX-Repop (p < 0.05).