Morphology of the facial nucleus of the rat.

The facial nucleus of the rat can be divided into 5 morphological subdivisions. Using a method for the correlation of the observed subdivisions with antidromic field profiles, the orgins of the major muscle branches of the facial nerve in the motor nucleus were determined. The posterior auricular branch is in the medial, the cervical in the ventromedial, the inferior and superior buccolabiales in the lateral, the zygomatic in the dorsal and the temporal and digastric in the intermediate subdivision. The results are consistent with an organization of the motor nucleus reflecting a corresponding topographic organization of the facial musculature.