Meeting Abstract

101.7  Thursday, Jan. 7  Sensory Stimulus and Reflex Response in Mammalian Swallowing GERMAN, RZ*; CROMPTON, AW; KONOW, N; THEXTON, AJ; Johns Hopkins Univ; Harvard Univ; Brown Univ; King’s College, London rz.german@jhmi.edu

Several sensory stimuli can elicit the reflex motor response of a mammalian pharyngeal swallow. Some, such as direct stimulation of a sensory nerve, are not within the range of normal stimuli an animal would experience. Of normal stimuli, bolus volume is the most frequently cited stimulus, although its exact role, and threshold is unknown. Our understanding of the swallow reflex is further complicated by the fact that the pharynx is a midline structure and several side-to-side sensory/motor brainstem connections exist. We tested the hypotheses that 1) stimuli other than bolus volume can elicit a swallow and 2) that unilateral stimuli are sufficient for a normal reflex response. Working with our infant pig model system and an automated feed delivery system, we measured the impact of non-pathologic stimuli on the initiation and frequency of swallowing. While bolus volume was one factor in eliciting a swallow, frequency of delivery, a stimulus to the anterior oral cavity was also significant. Further, some aspects of the motor response in feeding, such as frequency of intra-oral transport, are independent of changes in stimuli. When sensory nerves on one side are ligated, contralateral stimulation is sufficient to produce a kinematically normal swallow. These results are a first step to answering the question “what makes a swallow happen?”.