In hM4Di plus CNO subject mice, there was a significant reduction in mOT Fos expression compared with all other groups (Fig. 8C), suggesting that neuronal activity is diminished by CNO-induced DREADD receptor activation, and not by CNO alone or DREADD infection alone [main effects of drug treatment [F(1,41) = 15.4; p < 0.001bbb) and infection type (F(1,41) = 15.5; p < 0.001ccc), and interaction of infection type × drug treatment (F(1,41) = 9.7; p = 0.003ddd)]. Here, FOS is linked to infection.