Correlation of the main peripheral branches of the facial nerve with the cytoarchitectonic subdivisions of the facial nucleus in the guinea pig.

Correlation of the main peripheral branches of the facial nerve with morphological subdivisions of the facial nucleus was examined in the guinea pig by the retrograde horseradish peroxidase method. The facial nucleus of the guinea pig was divided cytoarchitectonically into the dorsolateral, lateral, intermediate, medio-intermediate, medial, and ventromedial divisions; the ventromedial division was further divided into the major, dorsal and lateral parts. Six main branches of the facial nerve were identified; the zygomatico-orbital, cervical, posterior auricular, anterior auricular, superior labial, and inferior labial branches. After applying HRP to the main branches of the facial nerve, the pattern of distribution of HRP-labelled neuronal cell bodies within the facial nucleus was examined: the dorsolateral division, dorsal part of the ventromedial division, major part of the ventromedial division, lateral part of the ventromedial division, or medial division contained the cell bodies of respectively the zygomatico-orbital, cervical, posterior auricular, anterior auricular, or superior labial branches, while each of the lateral, intermediate, and medio-intermediate divisions contained the cell bodies of both the superior labial and inferior labial branches.