Grn-/- mice (A, D, G; n=4) have an increase in the number and size of IBA-1-immunoreactive microglial cells compared to age-matched Grn+/+ mice (B, E, H; n=4) in the (A-C) hippocampus, (D-F) cortex, and (G-I) thalamus. Scale bar 200 μm in (A, B), 100 μm in (D, E), and 100 μm in (G, H). Percent thresholding shown in C, F, and I (Grn-/- in white, Grn+/+ in black) as mean ± SEM. Statistics denoted as p<0.05, * and p<0.01, **.