The density of c-Fos-positive cells in the NAcSh was significantly higher in TLR4
−/− than in WT mice after performing novelty-seeking behavior. A. Representative photomicrographs showing c-Fos-positive cells in the BLA, mPFCv, NAcSh, and PVT of WT (n = 5) and TLR4
−/− (n = 3) mice. B. Histograms quantifying the density of c-Fos-positive cells in the BLA, mPFCv, NAcSh, and PVT of WT and TLR4
−/− mice. BLA, basolateral amygdala; mPFCv, ventral medial prefrontal cortex; NAcSh, nucleus accumbens shell; PVT, paraventricular thalamic nucleus. Scale bar, 100 μm. **P < 0.01.