Correspondence between structure and function in the human brain at rest

Judith M Segall,Sunil K Arja,Kent Kiehl,Vince D Calhoun,Elena A Allen,Rex E Jung,Erik B Erhardt

doi:10.3389/fninf.2012.00010

Abstract

To further understanding of basic and complex cognitive functions, previous connectome research has identified functional and structural connections of the human brain. Functional connectivity is often measured by using resting-state functional magnetic resonance imaging (rs-fMRI) and is generally interpreted as an indirect measure of neuronal activity. Gray matter (GM) primarily consists of neuronal and glia cell bodies; therefore, it is surprising that the majority of connectome research has excluded GM measures. Therefore, we propose that by exploring where GM corresponds to function would aid in the understanding of both structural and functional connectivity and in turn the human connectome. A cohort of 603 healthy participants underwent structural and functional scanning on the same 3 T scanner at the Mind Research Network. To investigate the spatial correspondence between structure and function, spatial independent component analysis (ICA) was applied separately to both GM density (GMD) maps and to rs-fMRI data. ICA of GM delineates structural components based on the covariation of GMD regions among subjects. For the rs-fMRI data, ICA identified spatial patterns with common temporal features. These decomposed structural and functional components were then compared by spatial correlation. Basal ganglia components exhibited the highest structural to resting-state functional spatial correlation (r = 0.59). Cortical components generally show correspondence between a single structural component and several resting-state functional components. We also studied relationships between the weights of different structural components and identified the precuneus as a hub in GMD structural network correlations. In addition, we analyzed relationships between component weights, age, and gender; concluding that age has a significant effect on structural components.

Highlights

A central assumption of systems neuroscience is that the structure of the brain can predict and/or is related to functional connectivity
Out of the 10-by-30 structural and rs-functional component comparisons, 24 structural–functional component pairs were above the determined correlation coefficient threshold of |r| > 0.20
Our overall goal was to assess structural–functional relationships of the human brain and we found several gray matter (GM) structural components that spatially corresponded to rs-functional components

Summary

Introduction

A central assumption of systems neuroscience is that the structure of the brain can predict and/or is related to functional connectivity. People who recently acquired the ability to juggle exhibit changes in gray matter (GM) volumes of the mid-temporal area (MT/V5) and intraparietal sulcus (Draganski et al, 2004), in professional female ballet dancers there are distinct differences in white and gray matter compared to controls (Hanggi et al, 2010), and in musicians, greater cortical thickness is found in superior temporal and dorsolateral frontal regions as well, as increased GM concentration (GMC) in aspects of the Heschl’s gyrus (Bermudez et al, 2009) when compared to non-musicians These structural alterations reflect subjects’ specialized, and, in some cases, exceptional, functional abilities. The concept that the human brain is a complex network of neurons linking physical structure to function (Power et al, 2010) is not new to cognitive science

Methods

Results

Conclusion