Topographical arrangement of hypoglossal motoneurons: an HRP study in the cat.

Myotopical localization of hypoglossal motoneurons and representation of the main branches of the hypoglossal nerve within the hypoglossal nucleus were examined in the cat by the HRP method. The hypoglossal nucleus is divided cytoarchitectonically into the ventromedial and dorsolateral divisions; the medial and lateral branches of the hypoglossal nerve are represented respectively in the ventromedial and dorsolateral divisions. The genioglossus motoneurons are located in the ventrolateral part of the ventromedial division, and the geniohyoid motoneurons are in the most ventral part of the ventromedial division. The hypoglossus and styloglossus motoneurons are located in the lateral and dorsolateral parts of the dorsolateral division.