“…Application of subatmospheric airway pressure to the isolated upper airways of a variety of animal species (rats, rabbits, dogs, and cats) causes reflex activation in a variety of upper airway motor nerves and muscles, the latter including the alae nasi, tensor, and levator veli palatinae, palatoglossus, genioglossus, hyoglossus, geniohyoid, sternohyoid, sternothyroid, posterior cricoarytenoid, and cricothyroid (7,161,227,317,320,369,426,452,455,576,579). Where subatmospheric pressures have been sustained over several respiratory cycles, increases in upper airway motor activity during inspiration, as well as increases in tonic activity that persist in expiration are recorded (317,320,426,452,576,579). Reflex pharyngeal dilator muscle activation by subatmospheric airway pressure also occurs in humans (Fig.…”