Diffusion MRI

Psychology

Tractography

Artificial intelligence

Functional connectivity

Neuroscience

Magnetic resonance imaging

Human brain

Computer science

Radiology

Connectomics

Connectome

Human Connectome Project

Neuroimaging

Medicine

Science

A comprehensive description of how neurons and entire brain regions are interconnected is fundamental for a mechanistic understanding of brain function and dysfunction. Neuroimaging has shaped the way to approaching the human brain's connectivity on the basis of diffusion magnetic resonance imaging and tractography. At the same time, polarization, fluorescence, and electron microscopy became available, which pushed spatial resolution and sensitivity to the axonal or even to the synaptic level. New methods are mandatory to inform and constrain whole-brain tractography by regional, high-resolution connectivity data and local fiber geometry. Machine learning and simulation can provide predictions where experimental data are missing. Future interoperable atlases require new concepts, including high-resolution templates and directionality, to represent variants of tractography solutions and estimates of their accuracy.

Scale matters: The nested human connectome