As regards MeAV projections to the BST, it should be

noted that the tiny densely varicose subventricular foci (Figs. 3A, B, 6A) do not appear to correspond in location to the ejaculation-related clusters of Fos-immunorreactive neurons documented in rodents (Coolen et al., 1996 and Veening and Coolen, 1998), their functional implication being thus far unknown. Retrograde tracing observations in mice by Choi et al. (2005), in consonance with our own results, indicate that the MeAV innervates modestly the ventral premammillary nucleus and even more sparsely the medial preoptic nucleus. Having in mind that MeAV efferents also terminate rather modestly in the ventrolateral part of the ventromedial hypothalamic nucleus, and avoid almost completely the tuberal nucleus (present PHA-L observations), this scenario

suggest that the MeAV exerts little if any influence on key structures of a broad Venetoclax in vitro hypothalamic network subserving social behaviors (Motta et al., 2009, Newman, 1999, Simerly, 2002 and Swanson, 2000). Although Canteras and coworkers reliably Sunitinib supplier observed retrogradely labeled cells in ventral parts of the rat Me (including the MeAV) after injections in the dorsal premammillary nucleus (Comoli et al., 2000), they argued that this labeling probably reflects a spillover of the tracer into the ventral premammillary nucleus. The present PHA-L results indicating that the MeAV provides a clear input to the dorsal premammillary nucleus are in line with anterograde tracing studies (Gomez and Newman, 1992 and Luiten et al., 1985). A substantial retrograde labeling was noted in the MeAV after injections in the anterior hypothalamus (Choi et al., 2005 and Price et al., 1991; our own retrograde tracing experiments), however, the present anterograde tracing observations Baricitinib suggest that this nucleus is essentially traversed

by labeled poorly varicose passing fibers. It should be noted that in the present study MeAV projections were examined in females, whether these projections are sexually dimorphic remain to be determined. Remarkably, in spite of the low density of receptors for gonadal hormones in the anterior Me (Simerly et al., 1990), variations in the volume of the MeAV were reported during the estrous cycle, probably related to changes in estradiol levels (Carrillo et al., 2007). The possible functional significance of the MeAV is discussed based on its connectivity and on insights from studies using the expression of immediate early genes, as markers of neuronal activity (Fig. 12). The MeAV receives robust projections from the main and accessory olfactory systems (Canteras et al., 1995, Kemppainen et al., 2002, Luskin and Price, 1983, Majak and Pitkänen, 2003, McDonald, 1998, Petrovich et al., 1996 and Savander et al., 1996; present observations) including direct projections from the main olfactory bulb (Kang et al., 2009, Pro-Sistiaga et al.