Conduction velocity distributions compared to fiber size distributions in normal human sural nerve

Abstract

Compound action potentials (CAPs) were recorded from the sural nerve of healthy volunteers. A mathematical technique (inverse modeling) was used to compute conduction velocity (CV) histograms from the data. Results were compared to the morphology of age-matched nor mal sural nerve biopsies. Coefficients of variation (CoVs) revealed the statistical relationship between morphological data (diameter histo grams) and electrophysiological data (CV histograms and conventional CAP parameters). No differences were found for the thick fiber group when comparing the CoVs of the diameter histogram parameters with the corresponding CV histogram parameters. Apparently, the same in herent biological interindividual variability is encountered. The CoVs of the CVs of the CAP'S main phases are in good agreement with the CoVs of the estimated mean velocity of the thick fiber group. Inverse model ing increases the reliability of the estimation of the number of active fibers as compared to direct CAP amplitude interpretation.

A 3D Computational Model of Transcutaneous Electrical Nerve Stimulation for Estimating Aβ Tactile Nerve Fiber Excitability

“…The conduction velocities corresponding to varied fiber diameter were also shown in Figure 5. With the fiber diameter increasing from 2 to 8 μm, the corresponding conduction velocity increased from 5.68 to 33.14 m/s, which matched well with experimental data (Wesselink et al, 1999), and previously published modeling results in terms of small-diameter tactile sensory nerve fibers (Van Veen et al, 1995). The conduction velocity is dependent on a host of factors such as myelin sheath thickness and internodal length (Waxman, 1980).…”

“… Relationships between conduction velocities and fiber diameters: our TNF modeling (orange line), sensory fiber modeling (a Wesselink et al, 1999) and experimental data (b Van Veen et al, 1995) .…”

“…And, the 3 μm was most common diameter in the superficial cutaneous layer (Provitera et al, 2007). So the diameter of cutaneous Aβ nerve fiber is much compatible to the sural nerve fiber with 3.11 μm (Van Veen et al, 1995). The number of myelin lamellae and axon diameter was not constant, but decreased toward the distal end.…”

“…The conduction velocities were computed in NEURON corresponding to different fiber diameters ranging from 2 to 8 μm. The curves of conduction velocity vs. fiber diameters were compared with previously reported sensory fiber modeling results (Wesselink et al, 1999) and experimental data (Van Veen et al, 1995). In addition, with the stimulating frequency of 50 Hz and pulse duration of 200 μs, the strength-duration relationship in our 3D TENS model were achieved for a given Φ-9 mm electrode and an Φ-3 μm Aβ nerve fiber with typical electrical properties.…”

Electrically Evoked Compound Action Potential Recording in Peripheral Nerves

“…The various attempts to model the peripheral nerve ECAP from a peripheral nerve future science group www.futuremedicine.com rely on different simplifying assumptions, for instance that the form of the single fiber potential is consistent across the entire population or that the biological tissue can be considered a homogeneous conductor. The conduction velocity distributions of the sural nerve of the human have been estimated from ECAPs [46] and modeling.…”