The Corpus Callosum as a Model System in the Study of Mammalian Cerebral Axons
A large body of information is now available regarding the mechanism and the phenomonology of impulse conduction in invertebrate axons and in mammalian peripheral axons. Such axons, however, are of relatively large diameter when contrasted with their counterparts in the mammalian brain. Bishop (1966) has estimated that more than 80% of the fibers in the mammalian cortex are less than 3 μm in diameter, and in the pyramidal tract of the cat (Hildebrand and Skoglund, 1971) approximately 50% of the axons are less than 1 μm in diameter. The finest myelinated axons in the central nervous system are 0.2–0.3 μm in diameter (Bishop and Smith, 1964; Waxman and Bennett, 1972; Waxman and Swadlow, 1976a) while nonmyelinated axons may be as fine as 0.08 μm in diameter (Swadlow et al, 1980b; Waxman and Swadlow, 1976a).
KeywordsCorpus Callosum Test Stimulus Conduction Velocity Myelinated Axon Axonal Branch
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