Sexually Dimorphic Neurons in the Ventromedial Hypothalamus Govern Mating in Both Sexes and Aggression in Males

• Widespread adult sex differences in progesterone receptor (PR)-expressing neurons
• Ventrolateral compartment of ventromedial hypothalamus (VMHvl) contains PR+ neurons
• PR+ VMHvl neurons exhibit cellular and molecular dimorphisms between the sexes
• PR+ VMHvl neurons essential for normal mating in both sexes and fighting in males

SummarySexual dimorphisms in the brain underlie behavioral sex differences, but the function of individual sexually dimorphic neuronal populations is poorly understood. Neuronal sexual dimorphisms typically represent quantitative differences in cell number, gene expression, or other features, and it is unknown whether these dimorphisms control sex-typical behavior exclusively in one sex or in both sexes. The progesterone receptor (PR) controls female sexual behavior, and we find many sex differences in number, distribution, or projections of PR-expressing neurons in the adult mouse brain. Using a genetic strategy we developed, we have ablated one such dimorphic PR-expressing neuronal population located in the ventromedial hypothalamus (VMH). Ablation of these neurons in females greatly diminishes sexual receptivity. Strikingly, the corresponding ablation in males reduces mating and aggression. Our findings reveal the functions of a molecularly defined, sexually dimorphic neuronal population in the brain. Moreover, we show that sexually dimorphic neurons can control distinct sex-typical behaviors in both sexes.

Graphical AbstractFigure optionsDownload high-quality image (148 K)Download as PowerPoint slide