NEUROGENESIS OF AIRWAY PROTECTIVE BEHAVIORS IN THE CAT: COUGH AND PHARYNGEAL SWALLOW

Abstract

Neurons in the ventrolateral medulla involved in generating the motor pattern for breathing also have roles in the production of cough and swallowing behaviors. The reconfiguration of brainstem neural networks into selective behavioral control assemblies (BCAs) that govern different motor patterns required to optimize airway protection is not well understood. We challenged anesthetized cats with simultaneous cough and swallow‐producing stimuli to examine temporal relationships between these behaviors when co‐expressed. We also recorded from ventrolateral medullary respiratory neurons during cough and swallow. Swallows occurred during repetitive cough and were restricted to the cough E2 phase. The cough E2 phase was longer when a swallow occurred (3.7±1.5 s control, 5.7±1.5 s with swallow, p<0.002). Prolonged apnea occurred during repetitive swallow and was associated with increased tonic discharge of a subset of expiratory decrementing (E‐Dec) and silence of some inspiratory (I) neurons. Other E‐Dec and I neurons had phasic increases in discharge rate during swallow. The results support: a) an important role of E‐Dec neurons in coordinating cough and swallow, and b) complex coordination of these behaviors to ensure airway protection, presumably mediated by elements common to both cough and swallow BCAs. Supported by HL89104, HL89071, and NS19814.