Fig. 5
From: Aerodynamics and motor control of ultrasonic vocalizations for social communication in mice and rats
Embodied motor control model for rat USVs. A The impingement length (x), jet speed (u), and tracheal flow (V) change the B sound frequency. Black isolines indicate 10–100 kHz in 10 kHz steps. C Predicted flow by an orifice obstruction model (blue) corresponds well to measured flow (red) during subglottal pressure ramp through rat larynx in vitro (see the “Methods” section). D Jet speed shows little dependency on glottal area, but strongly increases with subglottal pressure. The vertical black lines represent half and twice the glottal areas measured from CT scans. E Effects of muscle shortening on laryngeal geometry (see the “Methods” section). Top, the cartilaginous glottis is affected by thyroarytenoid muscle (TA, orange arrow) and a combination of posterior cricoarytenoid (PCA) and interarytenoid (IA) muscles (green arrows). Bottom, contraction of the cricothyroid muscle (CT, cyan arrow) leads to thyroid rotation (black to cyan outline), which increases impingement length. The rotatory action of CT is assumed to be weakly counteracted by the smaller (TA) muscle. F Exploring the parameter space of our aerodynamic wall impingement model shows that both respiratory muscle (RM) and CT activity affect USV frequency. The whistle is unstable in the white area (see the “Methods” section). Black horizontal dashed line indicates the 3 kPa upper subglottal pressure limit during USVs in vivo. G TA action strongly influences the stability of the whistle and as such gates sounds, while it has little effect on f1. CT action affects both stability and f1. H Frequency f1 is highly redundant in the three-dimensional motor space (red isosurface; f1 = 45 kHz). At a given subglottal pressure (green isosurface; pt = 2.5 kPa) and flow (blue isosurface; V = 4.2 ml/s), this redundancy reduces into a single point. Dots indicate points where the USV is stable (color-coded for f1)