Schematic representation of the main olfactory (MOS) and vomeronasal systems (VNS) in mice. (A) Sensory neurons of the MOS are located in the nasal cavity at the olfactory epithelium (OE), Grüneberg ganglion (GG), and septal organ (SO), from where they send projections to the OB. Neurons of the VNS are located in the vomeronasal organ (VNO) and send axonal projections to the accessory olfactory bulb (AOB). (B) Central projections of the OB (pink and orange) terminate at the anterior olfactory nucleus (AON), tenia tecta (TT), olfactory tubercule (OT), piriform cortex (Pir), nucleus of the lateral olfactory tract (NLOT), anterior cortical nucleus (ACN) and posterolateral cortical nucleus (PLCN) of the amygdala, and entorhinal cortex (ENT). Central projections of the VNS are shown in dark gray, the accessory olfactory bulb (AOB) projects to the bed nucleus of the stria terminalis (BNST), the bed nucleus of the accessory olfactory tract (BAOT), the medial amygdala anteroventral (MEAav), posterodorsal (MEApd), posteroventral (MEApv), and posteromedial cortical nucleus (PMCN).