Local White Matter Architecture Defines Functional Brain Dynamics

TL;DR

This study demonstrates that variability in the local white matter connectome significantly correlates with and predicts differences in functional brain dynamics, supporting the idea that structural brain architecture constrains neural communication.

Contribution

The paper introduces a novel method for measuring local white matter integrity and shows its significant association with functional brain connectivity and dynamics.

Findings

Local connectome similarity correlates with functional connectivity patterns.

Segments of the local connectome can predict specific functional brain dynamics.

Structural variability constrains communication between brain regions.

Abstract

Large bundles of myelinated axons, called white matter, anatomically connect disparate brain regions together and compose the structural core of the human connectome. We recently proposed a method of measuring the local integrity along the length of each white matter fascicle, termed the local connectome. If communication efficiency is fundamentally constrained by the integrity along the entire length of a white matter bundle, then variability in the functional dynamics of brain networks should be associated with variability in the local connectome. We test this prediction using two statistical approaches that are capable of handling the high dimensionality of data. First, by performing statistical inference on distance-based correlations, we show that similarity in the local connectome between individuals is significantly correlated with similarity in their patterns of functional connectivity. Second, by employing variable selection using sparse canonical correlation analysis and cross-validation, we show that segments of the local connectome are predictive of certain patterns of functional brain dynamics. These results are consistent with the hypothesis that structural variability along axon bundles constrains communication between disparate brain regions.