DISTINCT AFFERENT SIGNATURES ONTO ANTERIOR AND POSTERIOR VMHVL SUBDOMAINS AND THEIR PROGESTERONE RECEPTOR-EXPRESSING NEURONS

Female sexual behavior is tightly coupled to reproductive state and requires the coordinated regulation of sexual receptivity and rejection across the estrous cycle. In mice, these opposing behaviors are controlled by distinct anteroposterior subdomains of the ventrolateral ventromedial hypothalamus (VMHvl): the posterior VMHvl (pVMHvl) promotes sexual receptivity, whereas the anterior VMHvl (aVMHvl) drives sexual rejection. Although progesterone receptor–expressing (PR⁺) neurons in both subregions are essential for these behaviors, the circuit mechanisms underlying this anteroposterior functional segregation remain poorly understood. Here, we investigated whether anterior and posterior VMHvl subdomains receive distinct afferent inputs that could support their divergent roles.
Using classic retrograde tracing combined with whole-brain, machine learning–assisted quantification, we mapped the afferent connectivity of the anterior and posterior VMHvl. We found that while the two subdomains share a majority of their inputs, they also receive distinct and biased projections. The aVMHvl preferentially receives inputs from the anterior hypothalamic nucleus, paraventricular and peripeduncular thalamic nuclei, and the parabrachial nucleus, whereas the posterior VMHvl is preferentially innervated by the preoptic area, ventral premammillary nucleus, anteroventral periventricular nucleus, and lateral septum. To determine whether these afferents target behaviorally relevant neurons, we performed monosynaptic rabies tracing from PR⁺ VMHvl neurons, which corroborated these domain-specific input signatures.
Together, our results reveal distinct afferent architectures onto anterior and posterior PR⁺ VMHvl neurons, providing a circuit-level framework for understanding how hormonal state flexibly biases female sexual behavior toward receptivity or rejection.