White-matter axon bundles retain stable statistics despite individual caliber variation
Published in Brain Architecture & Maps, Brain/Neurology, Journals, Numerical Simulations.
Published October 28, 2026.
An October 27 study in Communications Biology investigates whether variations in an axon’s thickness undermine estimates of nerve-signal conduction based on conventional tissue sections. Mordhorst and colleagues compared three-dimensional reconstructions with measurements that mimic two-dimensional histology.
Across approximately 450,000 reconstructed axons from male rats, individual fibers varied along their length, but bundles retained stable distributions of axon radius. Two-dimensional sections captured these ensemble distributions, and the modeled effect of within-axon variation on conduction velocity was modest. Large axons showed particularly stable predicted conduction.
The team then analyzed a dataset of 46 million human corpus-callosum axons to examine sampling requirements. Capturing the common small-axon population required fewer observations than reliably characterizing the rare large-axon tail.
The results support careful use of histological population statistics in brain-wiring research. They do not imply that individual axons are uniform, or directly measure every fiber’s signaling speed. Functional predictions depend on the biophysical model and sampled tissues; the study does not establish a clinical diagnostic test.
Source: Mordhorst et al., Communications Biology 9, 1410, October 27, 2026. DOI: 10.1038/s42003-026-11206-8.