Morphological Studies Of Expression Of VGLUT1 In The Vme Neurons And Pathways For Trigeminal Proprioception In The Rat

Trigeminal proprioceptive sensation play critical role in coordinating jaw movement. So it is necessary to study the trigeminal proprioceptive circuits for jaw reflexes and the pathways for proprioception to cerebellum or to cerebral cortex. However, little information is available about the orofacial proprioceptive circuits for reflexes and pathways for orofacial proprioception to cerebellum or cerebral cortex. Proprioceptive primary afferent neurons for the orofacial regions have been known to be located within the trigeminal mesencephalic nucleus (Vmes). Druring the past 30 years, we have found there exist two parallel pathways for orofacial proprioception from Vme to ventral posteromedial nucleus (VPM) of thalamus. One pathway consists of Vme, the dorsomedial part of the subnucleus oralis of the spinal trigeminal nucleus and and its adjacent reticular formation (Vodm-LRF), "zone shaped area" [which includes the dorsomedial part of the principal sensory trigeminal nucleus (Vpdm), the caudolateral part of the supratrigeminal nucleus (Vsup-CL), the dorsal area to the superior olivary nucleus (ADO) and the area ventral to the motor trigeminal nucleus (AVM)] and VPM, so named as "four-order pathway". Another pathway cosists of Vme, Vpdm and VPM, and so named as "three-order pathway". But the "four-order pathway" has not been widely accepted because of the imperfect methodology used in the previous studies.