CMAPS IN PHARYNGEAL AND HYOID MUSCLES EVOKED BY NUCLEUS SOLITARIUS STIMULATION IN DOGS

Electrical stimulation of the solitary nucleus with a single pulse of 150 to 500 mu A caused visible contractions of the muscles involved in swallowing but did not activate the central pattern generator for swa llowing. Electromyographically there were short bursts of activity cha racterized by an onset of activity within 1 to 7 ms, a duration of 14 to 26 ms, and an amplitude of 10 to 4,800 mu V. The CMAPs were recorde d in the pharyngeal and hyoid muscles on both the ipsilateral and the contralateral sides of the stimulated solitary nucleus. Across all fiv e pairs of muscles in which the recordings were made the latencies of the CMAPs in the contralateral muscles were significantly greater and the amplitudes significantly lower, but the durations were not signifi cantly different, Bilateral activation of the muscles by unilateral st imulation may not result in symmetrical contraction of the pharyngeal muscles.