PROJECTION OF DENTAL AFFERENT IMPULSES TO THE TRIGEMINAL NUCLEI OF THE CAT

Abstract

The pontine-bulbar projection of the pressure afferent from each tooth of the cat was determined, and the physiologic character of the response in the lower brain was analyzed. Each single tooth was pressed manually by a force meter (strain-gauge) and an evoked response in the pontine-bulbar region was recorded by means of microelectrode. The distribution of the responding spots in these areas was determined histologically. The responding spots localized in the ipsilateral trigeminal sensory nuclei at the levels between the brachium pontis and the obex. and these spots distributed mainly in the medial and central parts of the ipsilateral spinal nucleus and main sensory nucleus of the trigeminal nerve. Most of these spots in the nuclei responded to individual single teeth, but a few spots were recognized to receive impulses from several teeth. Information from the mandibular teeth projected more dorsally and medially in the nuclei than that from the maxillary teeth, whereby the molars projected more dorsally than the front teeth. Most of these spots responded to pressure on the teeth from all five directions, that is: axial, labio-lingual, lingo-labial, disto-medial and mediodistal, but some responded to the pressure given from specific directions only.