Superficial white matter fiber systems impede detection of long-range cortical connections in diffusion MR tractography

TLDR

Studying human brain anatomy is crucial, and diffusion MRI tractography is the primary tool for mapping long‑range projections that connect gray matter through deep white matter. The study combines dMRI tractography with histology to determine where the method succeeds and fails. The authors used dMRI tractography alongside histological analysis to assess the method’s performance across brain regions. The study finds that superficial white matter systems impede accurate measurement of cortical connections, highlighting a need to address these challenges for precise neuroanatomy.

Abstract

Significance It is widely recognized that studying the detailed anatomy of the human brain is of great importance for neuroscience and medicine. The principal means for achieving this goal is presently diffusion magnetic resonance imaging (dMRI) tractography, which uses the local diffusion of water throughout the brain to estimate the course of long-range anatomical projections. Such projections connect gray matter regions through axons that travel in the deep white matter. The present study combines dMRI tractography with histological analysis to investigate where in the brain this method succeeds and fails. We conclude that certain superficial white matter systems pose challenges for measuring cortical connections that must be overcome for accurate determination of detailed neuroanatomy in humans.