THE DIVERGENT PROJECTIONS IN THE BULBO-CEREBELLAR SYSTEM——A DOUBLE FLUORESCEIN LABELING STUDY / 解剖学报

ABSTRACT

The divergent projections in the bulbo-cerebellar system of rats were studied by double fluorescein labeling method. 2 ?1 of 2％ Fast blue (FB)were injected into the cerebellar cortex of left anterior lobe, 32 hours later, 2 ?l of 2％ Nuclear yellow (NY)were injected into the cerebellar cortex of right anteior lobe. The animals were allowed to survive 16 hours thereafter. Intracardiac perfusion were performed with 10％ formalin in 0.1 mol/L phosphate buffer. The cerebellum and medulla oblongata were removed and serial sections at 20 ?m were cut by cryostat. One of every two sections was preserved for fluorescence microscopic observation. The results identified that there was no intereonnection between the anterior lobes of two cerebellar hemispheres and the anterior lobe of cerebellum received afferent projections from much more nuclei of the medulla oblongata than previous description. The FB or NY single labeled and FB/NY double labeled cells were observed in the nucleus reticularis lateralis, subnucleus reticularis ventralis, nucleus raphe obscurus, nucleus prepositus hypoglossi, nucleus cuneatus lateralis, nucleus spinalis nervi trigemini and nucleus olivaris aceessorius dorsalis. The double labeled cells accounted for 23％ of total labeled cells except the nucleus olivaris inferior. The results mentioned above suggested that the cerebellum receive multiple afferent connections originated from the medulla oblongata, and the divergent projections further amplify the information-receiving areas in the cerebellum, and synchronize the activities of both cerebellar hemispheres.