Breathing Behaviors in Common Marmoset ( Callithrix jacchus )

The respiratory system maintains homeostatic levels of oxygen (O 2 ) and carbon dioxide (CO 2 ) in the body through rapid and efficient regulation of frequency and depth (tidal volume) of breathing. Many studies on homeostatic control of breathing have been done on rodent animal models, in which they have relatively reduced chemosensitivities when compared with primates. The use of common marmoset ( Callithrix jacchus ), a New World non-human primate model, in neuroscience is increasing, however, the data on their breathing is limited and their respiratory behaviors have yet to be characterized. Using Whole-body Plethysmography in room air as well as in hypoxic (low O 2 ) and hypercapnic (high CO 2 ) conditions, we defined breathing behaviors in awake, freely behaving marmosets. Additionally, we optimized an analysis toolkit for unsupervised analysis of respiratory activities in common marmoset. Our data indicate that marmosets’ exposure to hypoxia decreased metabolic rate and increased sigh rate. However, the hypoxic condition did not augment the ventilatory response. Hypercapnia, on the other hand, increased both the frequency and tidal volume. In this study, we described breathing behaviors of common marmosets in a variety of O 2 and CO 2 conditions.