The Origin of Spinocerebellar Pathways. I. The Nucleus Cervicalis Centralis of the Cranial Cervical Spinal Cord.

摘要

The origin of spinocerebellar projections from the cranial cervical spinal cord was studied in neonatal dogs following cerebellar ablations or the injection of horseradish peroxidase (HRP) into the cerebellum. Cerebellar ablations produced distinct retrograde changes of three types: Type I response or central chromatolysis; type II response or ghost cells; and type III response or neuronal loss and gliosis. These ablation-induced changes were evident in the cells of the nucleus cervicalis centralis. Anterograde fiber degeneration was present in the central cervical nucleus following dorsal rhizotomy in the dog and cat. These experiments demonstrated dorsal root fibers among the somata of central cervical neurons rendered chromatolytic following cerebellectomy in the dog. Electron microscopic evidence is presented for the presence of degenerated dorsal root terminals upon the dendrites and somata of central cervical neurons. The nucleus cervicalis centralis forms a direct link between neck afferents and the cerebellum by way of a crossed cervicospinocerebellar pathway. Evidence could not be found for the presence of a spinocerebellar projection originating in the nucleus cervicalis lateralis.