Biophysical Journal 8: 596-607 (1968)
© 1968 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Goldman, L. Articles by Albus, J. S. Search for Related Content PubMed PubMed Citation Articles by Goldman, L. Articles by Albus, J. S.

Computation of Impulse Conduction in Myelinated Fibers; Theoretical Basis of the Velocity-Diameter Relation

ABSTRACT

For myelinated fibers, it is experimentally well established that spike conduction velocity is proportional to fiber diameter. However no really satisfactory theoretical treatment has been proposed. To treat this problem a theoretical axon was described consisting of lengths of passive leaky cable (internode) regularly interrupted by short isopotential patches of excitable membrane (node). The nodal membrane was assumed to obey the Frankenhaeuser-Huxley equations. The explicit diameter dependencies of the various parameters were incorporated into the equations. The fiber diameter to axon diameter ratio was taken to be constant, and the internode length was taken to be proportional to the fiber diameter. Both these conditions reflect the situation that exists in real, experimental fibers. Dimensional analysis shows that these anatomical conditions are equivalent to Rushton's (1951) assumption of corresponding states. Hence, conduction velocity will be proportional to fiber diameter, in complete agreement with the experimental findings. Digital computer solutions of these equations were made in order to compute a set of actual velocities. Computations made with constant internode length or constant myelin thickness (i.e., nonconstant fiber diameter to axon diameter ratio) did not show linearity of the velocity-diameter relation.

This article has been cited by other articles:

				J. Lasiene, L. Shupe, S. Perlmutter, and P. Horner No Evidence for Chronic Demyelination in Spared Axons after Spinal Cord Injury in a Mouse J. Neurosci., April 9, 2008; 28(15): 3887 - 3896. [Abstract] [Full Text] [PDF]

				H. Wang, Y. Fu, P. Zickmund, R. Shi, and J.-X. Cheng Coherent Anti-Stokes Raman Scattering Imaging of Axonal Myelin in Live Spinal Tissues Biophys. J., July 1, 2005; 89(1): 581 - 591. [Abstract] [Full Text] [PDF]

				R. Amir and M. Devor Electrical Excitability of the Soma of Sensory Neurons Is Required for Spike Invasion of the Soma, but Not for Through-Conduction Biophys. J., April 1, 2003; 84(4): 2181 - 2191. [Abstract] [Full Text] [PDF]

				G. V. MANI, C. SHUREY, and C. J. GREEN Is Early Vascularization of Nerve Grafts Necessary? J Hand Surg Eur Vol., October 1, 1992; 17(5): 536 - 543. [Abstract] [PDF]

				P. Funch and D. Faber Measurement of myelin sheath resistances: implications for axonal conduction and pathophysiology Science, August 3, 1984; 225(4661): 538 - 540. [Abstract] [PDF]