Esr1+ cells in the ventromedial hypothalamus control female aggression

Esr1+ cells in the VMHvl are well known to influence female sexual behaviors. Here the authors find a surprising new role of this population in female aggression. They further reveal that the female VMHvl contains two molecularly and anatomically distinct subdivisions: one for aggression and one for sex. As an essential means of resolving conflicts, aggression is expressed by both sexes but often at a higher level in males than in females. Recent studies suggest that cells in the ventrolateral part of the ventromedial hypothalamus (VMHvl) that express estrogen receptor-α (Esr1) and progesterone receptor are essential for male but not female mouse aggression. In contrast, here we show that VMHvlEsr1+ cells are indispensable for female aggression. This population was active when females attacked naturally. Inactivation of these cells reduced female aggression whereas their activation elicited attack. Additionally, we found that female VMHvl contains two anatomically distinguishable subdivisions that showed differential gene expression, projection and activation patterns after mating and fighting. These results support an essential role of the VMHvl in both male and female aggression and reveal the existence of two previously unappreciated subdivisions in the female VMHvl that are involved in distinct social behaviors.