Mesencephalic nucleus of trigeminal nerve
It is functionally responsible for preventing excessive biting that may damage the dentition, regulating tooth pain perception, and mediating the jaw jerk reflex (by means of projecting to the motor nucleus of the trigeminal nerve).[2] The mesencephalic nucleus can thus be considered functionally as a primary sensory ganglion embedded within the brainstem,[1] making it neuroanatomically unique.[3] Unlike many nuclei within the central nervous system (CNS), the mesencephalic nucleus contains no chemical synapses, neurons instead being electrically coupled.The MNTN is involved in reflex proprioception of the periodontium[8] and of the muscles of mastication in the jaw[9] that functions to prevent biting down hard enough to lose a tooth.To subserve this reflex protective function, mechanoreceptive nerves in the periodontal ligament sense tooth movement and project to the mesencephalic nucleus.