Localization of the terminals of the tongue afferents in the nucleus of the solitary tract

Abstract

Abstract The nerves innervating the tongue were stimulated electrically and multineuron responses were recorded in the nucleus of the solitary tract. Stimulation of the chorda tympani and the IXth nerves evoked responses in the lateral and medial ipsilateral solitary nucleus in a rostral‐caudal order. Responses to lingual nerve stimulation were found only in the lateral, larger‐celled portion of the ipsilateral solitary nucleus overlapping the chorda tympani and the IXth nerve areas. Stimulation of the above three nerves also evoked somewhat longer latency responses in the ambiguus nucleus. Responses to lingual nerve stimulation were found in the XIIth nerve motor nucleus and the solitary nucleus at the level of the obex using high voltage levels of stimulation. The results were discussed in terms of the anatomical discreteness of the relays of the gustatory and the other tongue modalities in the solitary nucleus. These results were obtained in the white rats.