The detection of olfactory stimuli is essential for a variety of physiological and behavioral functions.  In a series of experiments, we examined the effects of pheromonal cues via bedding exposure on adult neurogenesis and revealed the role of the olfactory pathways on adult neurogenesis and behavior in the socially monogamous prairie vole (Microtus ochrogaster). In Experiment 1, subjects were injected with a cell proliferation marker, 5-bromo-2’-deoxyuridine (BrdU), and then exposed to their own soiled bedding or bedding soiled by a same- or opposite-sex conspecific. Exposure to opposite-sex bedding increased BrdU-labeling in the amygdala (AMY), but not the dentate gyrus (DG), of female, but not male, voles—indicating a sex-, stimulus-, and brain region-specific effect. In Experiment 2, the removal of the main olfactory bulbs or lesioning the vomeronasal organ (VNOX) in females reduced BrdU-labeling in the AMY and DG as well as inhibited the male bedding-induced BrdU-labeling in the AMY—revealing the importance of an intact olfactory pathway on amygdaloid neurogenesis. In Experiment 3, VNOX in female voles increased anxiety-like behavior and altered social preference, but did not affect social recognition memory. VNOX also reduced the percentage of BrdU-labeled cells that co-expressed the neuronal marker TuJ1 in the AMY, but not the DG.  Together, our data indicate the importance of the olfactory pathways in mediating brain plasticity in the limbic system as well as its role on behavior. (Supported by NIH grants MHR01-089852 and MHR01-58616)