Expression of IL-1R1 is required for RSD-induced recruitment of myeloid cells into the brain of GFP⁺ BM-chimeric mice. GFP⁺ BM-chimeric mice were generated in WT or IL-1R1^KO C57BL/6 mice and subjected to six cycles of RSD or left undisturbed as CON mice. Brains were collected 14 h after RSD for histology (n = 4–6). Representative images of GFP labeling (top) and GFP/Iba-1 co-labeling (bottom) in the AMYG WT–CON (A), WT–RSD (B), and IL-1R1^KO–RSD (C) mice are shown. Quantification of perivascular and parenchymal GFP⁺ macrophages in the PFC (D), AMYG (E), and HPC (F) are shown. Average proportional area of Iba-1+ labeling in the PFC (G), AMYG (H), and HPC (I) are shown. Bars represent average ± SEM. *p < 0.05, significantly different from CON.