Chapter 13 - Neuroendocrine control of vocalizations in rodents

Abstract

The neuroendocrine control of ultrasonic vocalizations (USVs) in rodents is a relatively understudied field; nonetheless, interesting findings regarding hormone-behavior relationships have emerged. Here, we focus on five rodent species in which most of this work has been done: golden hamsters (Mesocricetus auratus), house mice (Mus musculus), California mice (Peromyscus californicus), Alston’s singing mice (Scotinomys teguina), and rats (Rattus norvegicus). Many studies focus on sociosexual behavior and sex steroid hormones, however, there is a growing body of literature that probes other aspects of the impacts of neuroendocrine systems on rodent USVs. Using a comparative approach, we identify five major hormone-behavior concepts that are supported in the literature by at least one rodent species. Notably, the production of USVs in rodents can occur in the absence or presence of another individual and is particularly sensitive to social context. This leads us to ask whether (1) social context is critical for identifying sex steroid hormonal effects on USVs and whether (2) the internal energetic state, as represented by hunger hormones, is associated with changes in USVs. (3) We also review evidence for rapid effects of steroid hormone compounds on USVs and (4) research examining USVs as indicators of positive and negative affective states through the lens of hormones and neuroendocrine compounds. (5) Finally, because of the well-known effects of vasopressin and oxytocin on many social behaviors, including vocalizations, we examine the relationship of USV production to these neuropeptide hormones. Overall, there is a relative dearth of information on the function of many of the rodent USVs, with the exception of mate attraction, making it difficult to identify whether the effects of neuroendocrine compounds on USVs have an impact on social interactions, but emerging technology and call analysis tools are expected to advance our knowledge in this area. Through a comparative approach, this review highlights both common themes and a diversity of functions that arise from neuroendocrine influences on USV production.