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The origin of spinocerebellar pathways. I. The nucleus cervicalis centralis of the cranial cervical spinal cord
Author(s) -
Cummings J. F.,
Petras J. M.
Publication year - 1977
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.901730404
Subject(s) - spinal cord , anatomy , rhizotomy , cerebellum , chromatolysis , biology , cordotomy , nucleus , zona incerta , central nervous system , neuroscience , dorsum
The origin of spinocerebellar projections from the cranial cervi cal 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 cen tral chromatolysis; type II response or ghost cells; and type 111 response or neu ronal loss and gliosis. These ablation‐induced changes were evident in the cells of the nucleus cervicalis centralis . The results of hemicerebellectomy, unilateral cer ebellar pedunculotomy, and cordotomy established that the cells of this nucleus project contralaterally to the cerebellum. Cytoarchitectonic study revealed that this nucleus is composed of clustered medium‐sized, multipolar, chromatophilic neurons located in the zona intermedia of the C 1 ‐C 4 segments. The retrograde la beling of central cervical neurons following cerebellar injections of HRP con firmed the results obtained with the axonal reaction. 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 ceruicalis lateralis .