CEREBELLAR PROJECTION TO THE LOCUS CAERULEUS IN THE RABBIT / 解剖学报

ABSTRACT

Twenty five adult healthy rabbits were used in this study. They were divided into three experimental groups. In the first group, the great part of the left eerebellar hemisphere including the dentate nucleus was sucked out, a stereotaxic lesion of the left dentate nucleus was made, or a small part of the cerebellar cortex of hemisphere was destroyed. In the second group, the great part of the vermis was aspirated, the left fastigial nucleus or the vermal cortex was damaged with the stereotaxie electrolysis. In the third group, the left paraflocculus was sucked out. The animals survived for 3～8 days. The serial frozen transverse sections of the brain stem together with the cerebellum were cut at 25～30 ?m and stained with the Fink-Heimer method. The degenerating fibers in sections were traced under light microscope.The results are as follows1. The first group The degenerating fibers from the left dentate nucleus enter into the ipsilateral brachium conjunctivum, some of them emerge from the medial side of the brachium eonjunetivum, then proceed forward and pass through the trigeminal mesencephalie nucleus and end into the ipsilateral nucleus eaeruleus and subcaeruleus. But no degenerating fibers within nucleus caeruleus are observed if a lesion only injured the cerebellar cortex of hemisphere.2. The second group Except the projection to the cerebellar central nuclei and other regions of the brain stem, some degenerating fibers arising from the vermis (including vermal cortex and fastigial nucleus) ascend up into bilateral nucleus parabrachialis and a few of them enter into the ventral part of the brachium conjunctivum. These degenerating fibers continue forward to the rostral end of the pons and pass through the trigeminal mesencephalic nucleus to terminate in locus caeru leus and subcaeruleus.3. The third group A few degenerating fibers from the paraflocculus terminate in the locus caeruleus.The functional significance of the cerebellocaeruleus projection was discussed.