Abstract
Rats communicate extensively through ultrasonic vocalizations. In adult rats, these vocalizations occur in frequency bands centered at ~22 or ~50kHz. Twenty-two-kHz calls are emitted in association with negative emotional states whereas 50-kHz calls are produced in association with positive emotional states. One naturally suspects that the limbic system is engaged in initiating or processing these signals because limbic structures are known to be involved in aspects of emotional behavior. The goal of this review is to evaluate the role of the limbic system in initiating or processing ultrasonic vocalizations. Following a review of rat ultrasonic calls, we turn to the neuroanatomy of the limbic system, noting how the concept has evolved over the past century. The central focus is on the multiple lines of evidence linking certain limbic structures to aspects of the ultrasonic communication system. The implications of these findings for basic and translational research are considered.