Aerodynamics and motor control of ultrasonic vocalizations for social communication in mice and rats

Rodent ultrasonic vocalizations (USVs) are crucial to their social communication and a widely used translational tool for linking gene mutations to behavior. To maximize the causal interpretation of experimental treatments, we need to understand how neural control affects USV production. However, both the aerodynamics of USV production and its neural control remain poorly understood. Here we test three intralaryngeal whistle mechanisms - the wall and alar edge impingement, and shallow cavity tone - by combining in vitro larynx physiology and individual-based 3D airway reconstructions with fluid dynamics simulations. Our results show that in the mouse and rat larynx USVs are produced by a glottal jet impinging on the thyroid inner wall. Furthermore, we implemented an empirically based motor control model that predicts motor gesture trajectories of USV call types. Our work provides a quantitative neuromechanical framework to evaluate the contributions of brain and body in shaping USVs, and a first step in linking descending motor control to USV production.