Bilateral relationships of the trigeminal mesencephalic nuclei and mastication

A surgical procedure was developed in monkeys and cats to permit investigation of the central projections of the proprioceptors from the isolated medial or lateral pterygoid muscles, as well as from the intact masticatory muscle joint complex of the same animal. Evoked potentials were recorded simultaneously from the right and left mesencephalic nuclei of animals mounted in a Horsley‐Clark apparatus. All electrode placements were verified histologically. Depression of the mandible on the intact side of the head evoked potentials in the ipsi‐ and contralateral mesencephalic nuclei, as did tension applied to the isolated medial or lateral pterygoid muscle. It is believed that these potentials are representative of impulses projected via a polysynaptic chain from the nuclear chain type of neuromuscular spindles, Golgi tendon organs and joint receptors, each of which projects bilaterally and contributes to the correlation and integration of the function of the muscles of mastication.