Figure 4.

Representative images of mediodorsal thalamus and ROIs. Expression of c-Fos in mediodorsal thalami of the novel groups (left column) and familiar groups (right column) in response to an odor (top), a taste (middle), or an odor-taste mixture (bottom). Middle column displays enlarged images of the boxed areas. Greater expression of c-Fos is observed after exposure to odorized water that is novel than when familiar, whereas c-Fos expression is greater after exposure to familiar taste alone or an odor-taste mixture than with a novel taste or a novel odor-taste mixture, respectively. There were no significant differences in ROI areas across sections or groups. Scale bar: 1-mm low magnification; 250-µm high magnification. Abbreviations: LHb, lateral habenular nucleus; MD, mediodorsal thalamus; MHb, medial habenular nucleus; PVP, paraventricular thalamic nucleus.