A Labeled-Line Neural Circuit for Pheromone-Mediated Sexual Behaviors in Mice.

In mice, various instinctive behaviors can be triggered by olfactory input. Despite growing knowledge of the brain regions involved in such behaviors, the organization of the neural circuits that convert olfactory input into stereotyped behavioral output remains poorly understood. Here, we mapped the neural circuit responsible for enhancing sexual receptivity of female mice by a male pheromone, exocrine gland-secreting peptide 1 (ESP1). We revealed specific neural types and pathways by which ESP1 information is conveyed from the peripheral receptive organ to the motor-regulating midbrain via the amygdala-hypothalamus axis. In the medial amygdala, a specific type of projection neurons gated ESP1 signals to the ventromedial hypothalamus (VMH) in a sex-dependent manner. In the dorsal VMH, which has been associated with defensive behaviors, a selective neural subpopulation discriminately mediated ESP1 information from a predator cue. Together, our data illuminate a labeled-line organization for controlling pheromone-mediated sexual behavioral output in female mice.