Sex selectivity of mouse ultrasonic songs.

In many species, reproduction requires detecting, recognizing, and courting a potential mate. Progress through these stages is guided by cues involving a wide range of sensory systems. Here we explore the tasks of detection, recognition, and response in terms of the ultrasonic songs of male mice presented with odor cues contained in urine. We find that the quantity of singing, more so than specific features of the songs, varies depending upon the odor cue. For experienced male mice, responses to female odor cues depend only on the concentration of female cues and are independent of the presence of male cues. However, for naive mice, male cues appear to be synergistic for the response to female cues. We therefore find no direct behavioral evidence for a role of opponent neural processing, such as lateral inhibition, in distinguishing sex by olfactory cues. However, modeling demonstrates that lateral inhibition could be one possible mechanism to account for the switch from synergy to independence.