Central origin of canine vidian nerve studied by the HRP method

Central origin of the vidian nerve in the dog was investigated using the retrograde tracing technique of horseradish peroxidase (HRP). After HRP was applied to the vidian nerve, labelled neurons were found in the medulla oblongata and the geniculate ganglion but could not be found in the trigeminal ganglion. Labelled neurons in the medulla oblongata were found not only in the dorsal part but also in the ventral part to the facial motor nucleus and were maximum in number at the level of the rostral third of the facial motor nucleus. These labelled neurons were generally medium-sized multipolar neurons with well-developed dendrites.