A physical perspective to understand myelin. I. Peters quadrant mystery

TL;DR

This study uses biophysical modeling to explain the Peters quadrant mystery in myelin development, revealing how electric fields influence the positioning of myelin components within the same quadrant.

Contribution

It introduces a detailed biophysical simulation demonstrating how electric fields and low impedance channels explain the Peters quadrant mystery in oligodendrocyte development.

Findings

High-current zones form around the inner and outer tongue due to low impedance channels.

Same quadrant positioning causes voltage polarity reversal at the inner tongue.

External electric fields can promote or inhibit myelin growth.

Abstract

In the development of oligodendrocytes in the central nervous systems, the inner and outer tongue of the myelin sheath tend to be located within the same quadrant, which was named as Peters quadrant mystery. In this study, we conduct in silico investigations to explore the possible mechanisms underlying the Peters quadrant mystery. A biophysically detailed model of oligodendrocytes was used to simulate the effect of the actional potential-induced electric field across the myelin sheath. Our simulation suggests that the paranodal channel connecting the inner and outer tongue forms a low impedance route, inducing two high-current zones at the area around the inner and outer tongue. When the inner tongue and outer tongue are located within the same quadrant, the interaction of these two high-current-zones will induce a maximum amplitude and a polarity reverse of the voltage upon the inner tongue, resulting in the same quadrant phenomenon. This model indicates that the growth of myelin follows a simple principle: an external negative or positive E-field can promote or inhibit the growth of the inner tongue, respectively.