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Morphology of single olivocerebellar axons labeled with biotinylated dextran amine in the rat
Author(s) -
Sugihara I.,
Wu H.S.,
Shinoda Y.
Publication year - 1999
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/(sici)1096-9861(19991115)414:2<131::aid-cne1>3.0.co;2-f
Subject(s) - biotinylated dextran amine , cerebellum , axon , granular layer , anatomy , biology , white matter , neuroscience , medicine , magnetic resonance imaging , radiology
The morphology of olivocerebellar (OC) axons originating from the inferior olive (IO) was investigated in the rat by reconstructing the entire trajectories of single axons that had been labeled with biotinylated dextran amine. Virtually all of the OC axons entered the cerebellum through the inferior cerebellar peduncle (ICP) contralateral to the IO, with a few exceptions. Although most OC projection was contralateral, a few axons projected bilaterally by crossing the midline within the cerebellum. Collaterals of OC axons could be classified into thick branches and thin collaterals. Thick branches of each OC axon (6.1 ± 3.7/OC axon, mean ± SD for n = 16 axons) terminated as climbing fibers (CFs) on single Purkinje cells (PCs) in a one‐to‐one relationship. Besides terminal arborization around PC thick dendrites, CFs had terminals that surrounded a PC soma, fine branchlets that extended transversely in the molecular layer, and thin retrograde collaterals that re‐entered the PC and granular layers. Innervation of a single PC by two CFs originating from the same axon was seen, although infrequently. Concerning thin collaterals, about half of the OC axons had one or only a few collaterals terminating in the white matter of the ICP, most had 1 to 6 collaterals terminating in a single cerebellar nucleus, and all had 3 to 16 collaterals that terminated mainly in the granular layer, but occasionally in the cerebellar white matter and the PC layer. Some swellings of thin collaterals touched somata of presumed Golgi cells and PCs. No OC axons terminated solely in the ICP, cerebellar nucleus or granular layer without giving rise to CFs. J. Comp. Neurol. 414:131–148, 1999. © 1999 Wiley‐Liss, Inc.