A model of the electrical behaviour of myelinated sensory nerve fibres based on human data

Abstract

Calculation of the response of human myelinated sensory nerve fibres to spinal cord stimulation initiated the development of a fibre model based on electrophysiological and morphometric data for human sensory nerve fibres. The model encompasses a mathematical description of the kinetics of the nodal membrane, and a non-linear fibre geometry. Fine tuning of only a few, not well-established parameters was performed by fitting the shape of a propagating action potential and its diameter-dependent propagation velocity. The quantitative behaviour of this model corresponds better to experimentally determined human fibre properties than other mammalian, nonhuman models do. Typical characteristics, such as the shape of the action potential, the propagation velocity and the strength-duration behaviour show a good fit with experimental data. The introduced diameter-dependent parameters did not result in a noticeable diameter dependency of action potential duration and refractory period. The presented model provides an improved tool to analyse the electrical behaviour of human myelinated sensory nerve fibres.

Targeted Subcortical Nerve Recruitment by Controlling the Waveform of Electrical Stimulation for MRI-guided Surgical Ablation

“…1Aa and Table 1). To imitate the cortico-cortical pathway, a model of the human myelinated nerve ber [12,13] was embedded in the white matter parallel to the skull (Fig. 1Ab). …”

“…The model of a nerve ber of the human spinal cord [12,13] was positioned at a distance of 5.1 mm through 5.7 mm from the cortex, parallel to the skull in the white matter (Fig. 1Ab).…”

“…However, the authors who originally developed the nerve ber model assumed the diameters of the bers to be over 5 μm [13], and no description was found for bers thinner than 5 μm. Thus, we assumed the following equations for bers thinner than 5 μm by extrapolating the de ned range: Layers II-IV 1.4 0.36 [4,9] Layers V-VI 2.1 0.36 [4,9] White matter 12 0.083 (perpendicular to the ber), 0.6 (parallel to the ber) [4,9] Advanced Biomedical Engineering.…”

A new pulse shape to obtain selective small fiber activation by anodal blocking

“…The second part was a human fiber model [9]. With this model, it is possible to simulate excitation and blocking of an AP in myelinated fibers.…”

“…A symmetrical tripolar cuff electrode with an inner diameter of 2 mm was placed around a sacral root of 1.4 mm diameter. The distance between contacts was 3 mm and the total length of the cuff was 8 mm.The second part was a human fiber model [9]. With this model, it is possible to simulate excitation and blocking of an AP in myelinated fibers.…”