Mesencephalic nucleus of trigeminal nerve

The mesencephalic nucleus is involved with proprioception, that is, the feeling of position of the muscles. Unlike many nuclei within the CNS, the mesencephalic nucleus contains no chemical synapses but are electrically coupled (Baker and Llinas1971). Instead, neurons of this nucleus are pseudounipolar cells receiving proprioceptive information from the jaw, and sending projections to the motor trigeminal nucleus to mediate monosynaptic jaw reflexes.

Baker, R.G. and Llinas, R. Electrotonic coupling between neurones in the rat mesencephalic nucleus. J. Physiology 212: 45-63, 1971.