Comparative Connectomics: Mapping the Inter-Individual Variability of Connections within the Regions of the Human Brain

TL;DR

This study maps the variability of brain connections across individuals using diffusion MRI, revealing that certain brain regions are more consistent while others show high diversity in their connectivity patterns.

Contribution

It provides a comprehensive comparison of individual human brain connectomes, highlighting regional differences in inter-individual variability.

Findings

Frontal and limbic lobes are more conservative in connectivity.

Temporal and occipital lobes show higher diversity.

Specific smaller regions exhibit distinct variability patterns.

Abstract

The human braingraph, or connectome is a description of the connections of the brain: the nodes of the graph correspond to small areas of the gray matter, and two nodes are connected by an edge if a diffusion MRI-based workflow finds fibers between those brain areas. We have constructed 1015-vertex graphs from the diffusion MRI brain images of 395 human subjects and compared the individual graphs with respect to several different areas of the brain. The inter-individual variability of the graphs within different brain regions was discovered and described. We have found that the frontal and the limbic lobes are more conservative, while the edges in the temporal and occipital lobes are more diverse. Interestingly, a "hybrid" conservative and diverse distribution was found in the paracentral lobule and the fusiform gyrus. Smaller cortical areas were also evaluated: precentral gyri were found to be more conservative, and the postcentral and the superior temporal gyri to be very diverse.