axons

Axon models

oSPARC-vns uses customised models based on observed distributions of axon populations, such as the following:

reference: Pereyra, Zhang, Schmidt, & Becker (1992).

These were digitised and used to generate axon populations whose axon diameters and g-ratios followed this distribution. This are also where the default axons densities came from.

Myelinated axon model for afferent and efferent axons, adapted from Gaines 2016

Visceral myelinated axons can have smaller diameters than somatic myelinated axons, outside the range for the ultrastructural relationships presented in (McIntyre et al., 2002). The published interpolations (McIntyre et al., 2002) fail to extrapolate to these small myelinated axon diameters. To model the distribution of fiber diameters and g-ratios measured for myelinated axons in visceral nerve, we related the axon diameter and compartment length at each of the node of Ranvier (NODE), paranode (MYSA), juxtaparanode (FLUT) and stereotypical internode (STIN). This work is currently under review.

Myelinated axon model for afferent and efferent axons, adapted from Sundt 2015

The axon model was derived from the peripheral axon segment model and did not contain KCNQ or Ca2+-dependent K+ channels. All channel kinetics were adjusted using Q10 factors to simulate body temperature. The unmyelinated axon model did not contain detailed representations of the axon ultrastructure and was modelled as a multi-segment single-cable model (20 µm per segment).