Representation of the masticatory muscles in the motor trigeminal nucleus of the macaque monkey.

The pattern of representation of the masticatory muscles in the motor trigeminal nucleus was examined in macaque monkeys by the horseradish peroxidase method. The motor trigeminal nucleus was divided cytoarchitectonically into the dorsolateral and ventromedial divisions. The temporalis, masseter and pterygoid muscles were represented in the dorsomedial, central and ventrolateral parts of the dorsolateral division, respectively. In the ventromedial division, which was located at the level of the caudal half of the nucleus. The anterior digastric or mylohyoid muscle was represented in the dorsomedial or ventrolateral part of the division, respectively.