Ethanol causes a significant increase in cFos expression in the lateral habenula (LHb). Images of three rostrocaudal levels demonstrate cFos expression in the LHb, medial habenula (MHb) and paraventricular thalamic nucleus (PVP) at 90 min after an intraperitoneal injection of saline (A-C) or 0.25 g/kg ethanol (EtOH, A1-C1). (D-F)Summary graph of the increase of cFos immunoreactive cell density in the LHb, but not in the MHb, and PVP at 90 min, 4 h and 8 h after the injection of saline or ethanol (0.25 and 0.5 g/kg). Since there was no difference in cFos expression in the LHb of rats treated with saline across the various time points, the data across time points were collapsed for analysis. ***p < 0.001 vs. any other groups. ###p < 0.001 vs. saline. n=8-10 rats/group, unpaired t-test; Scale bar =200 μm.