Identification of motoneurons in the nucleus ambiguus by antidromic stimulation of the superior and the recurrent laryngeal nerves in rats.

Motoneurons in the nucleus ambiguus (NA) for the superior and the recurrent laryngeal nerves were identified by antidromic stimulation of these nerves in rats anesthesized with urethane. Two subpopulations of NA motoneurons were distinguished in the ventrolateral medullary region: (1) NA motoneurons from which antidromically evoked action potentials by stimulation of the superior laryngeal nerve were recorded were found in the ventral formation; and (2) neurons activated antidromically by stimulation of the recurrent laryngeal nerve were in the dorsal formation of NA. These findings are in good agreement with previous morphological studies.