[Primary trigemino-cerebellar afferents demonstrated by the method of fluorescent retrograde double labeling in rats].

Two axonally transported fluorescent substances, Granular Blue and Nuclear Yellow, were applied in the mandibular nerve and in the entire half of ipsilateral cerebellar cortex respectively. Observations of serial slices by using fluorescent photonic microscope showed double marked cells in the caudal part of homolateral trigemino-mesencephalic nucleus. Cells body had a 28-35 microns diameter and showed an oval-shaped and a pseudo-unipolar type. Numbers of neurons were no more than 10-15 per animal. There was no indication of double coloured cells either in the trigeminal ganglion or in the adjacent bulbo-reticulo-pontic regions. It is concluded that identified neurons have their origin into periodontical structures. They bring the proof of non-vestibular direct cerebellar pathways.