Correlated Disorder in Myelinated Axons Orientational Geometry and Structure

While the ultrastructure of the myelin has been considered to be a quasi-crystalline stable system, nowadays its multiscale complex dynamics appears to play a key role for its functionality, degeneration and repair processes following neurological diseases and trauma. In this work, we have investigated the interactions between axons associated to the nerve functionality, measuring the spatial distribution of the orientation fluctuations of axons in a Xenopus Laevis sciatic nerve. At this aim, we have used scanning micro X-ray diffraction (SμXRD), a non-invasive technique already applied to other heterogeneous systems presenting complex geometries from microscale to nanoscale. We have found that the orientation spatial fluctuations of fresh axons show a Levy flight distribution which is a direct indication of correlated disorder. We have found that the Levy flight distribution is missing in the aged nerve prepared in the unfresh state. This result shows that the spatial distribution of axons orientation fluctuations in unfresh nerve state loose the correlated disorder assuming the random disorder behavior. This work allows a deeper understanding of the ultrastructure-function nerve relation and paves the way to study other materials and biomaterials using SμXRD technique to detect fluctuations of their supramolecular structure.