Noisy saltatory spike propagation: The breakdown of signal transmission due to channel noise

TL;DR

This paper investigates how intrinsic channel noise affects the reliability of saltatory spike propagation in myelinated axons, revealing that increased noise can cause a breakdown in signal transmission.

Contribution

It extends previous models by analyzing the impact of stronger channel noise and supra-threshold coupling on spike transmission reliability in a stochastic Hodgkin-Huxley framework.

Findings

Signal transmission reliability decreases with increasing channel noise.

High noise levels can cause complete breakdown of spike propagation.

Reliability loss occurs under strong supra-threshold coupling and high noise.

Abstract

Noisy saltatory spike propagation along myelinated axons is studied within a stochastic Hodgkin-Huxley model. The intrinsic noise (whose strength is inverse proportional to the nodal membrane size) arising from fluctuations of the number of open ion channels influences the dynamics of the membrane potential in a node of Ranvier where the sodium ion channels are predominantly localized. The nodes of Ranvier are linearly coupled. As the measure for the signal propagation reliability we focus on the ratio between the number of initiated spikes and the transmitted spikes. This work supplements our earlier study [A. Ochab-Marcinek, G. Schmid, I. Goychuk and P. H\"anggi, Phys. Rev E 79, 011904 (2009)] towards stronger channel noise intensity and supra-threshold coupling. For strong supra-threshold coupling the transmission reliability decreases with increasing channel noise level until the causal relationship is completely lost and a breakdown of the spike propagation due to the intrinsic noise is observed.