The facial outflow and the superior salivatory nucleus: An histochemical study in the rat

Abstract

Abstract Shute and Lewis ('60) presented the first definite evidence for the localization of the superior salivatory nucleus by means of the thiocholine method for demonstrating cholinestrase. The outflow from this nucleus postulated by these workers is questionable in the light of other observations (Brown, '64). A re‐investigation of the salivatory nuclei in the rat by the thiocholine method in conjunction with three‐dimensional reconstructions shows that two topographically related cholinesterasepositive pathways are present at facial levels. These are the visceral motor (salivatory) rootlets and the olivo‐cochlear tract. The reconstructions decisively indicate a typical visceral motor outflow to the nervus intermedius from the superior salivatory nucleus and endorse Rasmussen's description of the olivo‐cochlear tract.