248 ILAR Journal

Sleep-disordered breathing comprises alterations in respira-tory rate, rhythm, and depth that present during sleep and may or may not be recognizable in breathing during wake-fulness. Primary disorders include repetitive apneas, near apneas (hypopneas), or reductions in overall ventilation dur-ing sleep (hypoventilation), all of which lead to reductions in pulmonary gas exchange resulting in arousals, arrhythmia, hypercapnia, acidosis, and/or hypoxic stress responses such as pulmonary hypertension or polycythemia. Because the underlying mechanisms resulting in sleep-disordered breath-ing and its resulting comorbidities remain unclear, research-ers use a variety of animal models to better understand the disorder. These models allow for conditioning paradigms, more detailed measurements of respiratory control, and th