Modular Brain Networks

Abstract

The development of new technologies for mapping structural and functional brain connectivity has led to the creation of comprehensive network maps of neuronal circuits and systems. The architecture of these brain networks can be examined and analyzed with a large variety of graph theory tools. Methods for detecting modules, or network communities, are of particular interest because they uncover major building blocks or subnetworks that are particularly densely connected, often corresponding to specialized functional components. A large number of methods for community detection have become available and are now widely applied in network neuroscience. This article first surveys a number of these methods, with an emphasis on their advantages and shortcomings; then it summarizes major findings on the existence of modules in both structural and functional brain networks and briefly considers their potential functional roles in brain evolution, wiring minimization, and the emergence of functional specialization and complex dynamics.

Network architecture of the cerebral nuclei (basal ganglia) association and commissural connectome

“…For single-hemisphere interconnections, modules were detected by modularity maximization while systematically varying a spatial resolution parameter γ to assess module stability (9,14). Varying γ within the interval [0.5-1.5] centered on the default setting of γ = 1 resulted in four stable solutions ( Fig.…”

“…The present study reexamines the organization of axonal connections between all parts of the cerebral nuclei, using systematic, data-driven, network analysis methods (8,9). The analysis is based on a directed, weighted macroconnectome of association connections (between ipsilateral parts) and commissural connections (between parts on one side and those on the other side), using the same basic strategy and methodology applied to the rat cerebral cortical association macroconnectome (10) but with additional analytical approaches and curation tools.…”

Brain network modules of meaningful and meaningless objects

“…This modularity was shown to support sustaining wiring cost and creating specialized information [3]. Modularity of brain networks forms how information is circulated and processed: functionally neighboring regions tend to share information are participating in the same module.…”

“…Modularity of brain networks forms how information is circulated and processed: functionally neighboring regions tend to share information are participating in the same module. Thus, modular networks allow for better information processing than nonmodular systems [3].…”

“…Methods for detecting modularity usually detect subnetworks that are densely interconnected but externally weakly connected [3], also called network communities which correspond to particular cognitive functions. Modularity was shown to be an essential property of many brain functions such as learning [4] and other various cognitive tasks [5].…”