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Connectomic Insights into Topologically Centralized Network Edges and Relevant Motifs in the Human Brain.

Xia M, Lin Q, Bi Y, He Y - Front Hum Neurosci (2016)

Bottom Line: We found that the pivotal WM connections with highly topological-edge centrality were primarily distributed in several long-range cortico-cortical connections (including the corpus callosum, cingulum and inferior fronto-occipital fasciculus) and some projection tracts linking subcortical regions.Computational simulation models indicated the sharp decrease of global network integrity when attacking these highly centralized edges.Together, our results demonstrated high building-cost consumption and substantial communication capacity contributions for pivotal WM connections, which deepens our understanding of the topological mechanisms that govern the organization of human connectomes.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University Beijing, China.

ABSTRACT
White matter (WM) tracts serve as important material substrates for information transfer across brain regions. However, the topological roles of WM tracts in global brain communications and their underlying microstructural basis remain poorly understood. Here, we employed diffusion magnetic resonance imaging and graph-theoretical approaches to identify the pivotal WM connections in human whole-brain networks and further investigated their wiring substrates (including WM microstructural organization and physical consumption) and topological contributions to the brain's network backbone. We found that the pivotal WM connections with highly topological-edge centrality were primarily distributed in several long-range cortico-cortical connections (including the corpus callosum, cingulum and inferior fronto-occipital fasciculus) and some projection tracts linking subcortical regions. These pivotal WM connections exhibited high levels of microstructural organization indicated by diffusion measures (the fractional anisotropy, the mean diffusivity and the axial diffusivity) and greater physical consumption indicated by streamline lengths, and contributed significantly to the brain's hubs and the rich-club structure. Network motif analysis further revealed their heavy participations in the organization of communication blocks, especially in routes involving inter-hemispheric heterotopic and extremely remote intra-hemispheric systems. Computational simulation models indicated the sharp decrease of global network integrity when attacking these highly centralized edges. Together, our results demonstrated high building-cost consumption and substantial communication capacity contributions for pivotal WM connections, which deepens our understanding of the topological mechanisms that govern the organization of human connectomes.

No MeSH data available.


Contribution of the pivotal edges toward the centrality of the nodes they linked. The pivotal edges had significantly greater contributions to all three nodal properties (nodal degree, efficiency, and betweenness) than the non-pivotal ones. The contribution toward nodal centralities of an edge was estimated by averaging nodal properties of its two linking nodes.
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Figure 3: Contribution of the pivotal edges toward the centrality of the nodes they linked. The pivotal edges had significantly greater contributions to all three nodal properties (nodal degree, efficiency, and betweenness) than the non-pivotal ones. The contribution toward nodal centralities of an edge was estimated by averaging nodal properties of its two linking nodes.

Mentions: We explored the relationship between the EBC values of WM edges and their linked nodes' properties (nodal degree, efficiency, and betweenness). The pivotal edges had significantly greater contributions to all three nodal properties than the non-pivotal ones (all ps < 0.0001, permutation tests) (Figure 3). Moreover, significant positive correlations were found over all three nodal centralities and across all edges, with the Spearman's correlation coefficients of 0.35, 0.38, and 0.59, respectively (all ps < 0.0001) (Table S1). These results indicated a strong topological nexus between pivotal edges and pivotal nodes in the WM network.


Connectomic Insights into Topologically Centralized Network Edges and Relevant Motifs in the Human Brain.

Xia M, Lin Q, Bi Y, He Y - Front Hum Neurosci (2016)

Contribution of the pivotal edges toward the centrality of the nodes they linked. The pivotal edges had significantly greater contributions to all three nodal properties (nodal degree, efficiency, and betweenness) than the non-pivotal ones. The contribution toward nodal centralities of an edge was estimated by averaging nodal properties of its two linking nodes.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835491&req=5

Figure 3: Contribution of the pivotal edges toward the centrality of the nodes they linked. The pivotal edges had significantly greater contributions to all three nodal properties (nodal degree, efficiency, and betweenness) than the non-pivotal ones. The contribution toward nodal centralities of an edge was estimated by averaging nodal properties of its two linking nodes.
Mentions: We explored the relationship between the EBC values of WM edges and their linked nodes' properties (nodal degree, efficiency, and betweenness). The pivotal edges had significantly greater contributions to all three nodal properties than the non-pivotal ones (all ps < 0.0001, permutation tests) (Figure 3). Moreover, significant positive correlations were found over all three nodal centralities and across all edges, with the Spearman's correlation coefficients of 0.35, 0.38, and 0.59, respectively (all ps < 0.0001) (Table S1). These results indicated a strong topological nexus between pivotal edges and pivotal nodes in the WM network.

Bottom Line: We found that the pivotal WM connections with highly topological-edge centrality were primarily distributed in several long-range cortico-cortical connections (including the corpus callosum, cingulum and inferior fronto-occipital fasciculus) and some projection tracts linking subcortical regions.Computational simulation models indicated the sharp decrease of global network integrity when attacking these highly centralized edges.Together, our results demonstrated high building-cost consumption and substantial communication capacity contributions for pivotal WM connections, which deepens our understanding of the topological mechanisms that govern the organization of human connectomes.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University Beijing, China.

ABSTRACT
White matter (WM) tracts serve as important material substrates for information transfer across brain regions. However, the topological roles of WM tracts in global brain communications and their underlying microstructural basis remain poorly understood. Here, we employed diffusion magnetic resonance imaging and graph-theoretical approaches to identify the pivotal WM connections in human whole-brain networks and further investigated their wiring substrates (including WM microstructural organization and physical consumption) and topological contributions to the brain's network backbone. We found that the pivotal WM connections with highly topological-edge centrality were primarily distributed in several long-range cortico-cortical connections (including the corpus callosum, cingulum and inferior fronto-occipital fasciculus) and some projection tracts linking subcortical regions. These pivotal WM connections exhibited high levels of microstructural organization indicated by diffusion measures (the fractional anisotropy, the mean diffusivity and the axial diffusivity) and greater physical consumption indicated by streamline lengths, and contributed significantly to the brain's hubs and the rich-club structure. Network motif analysis further revealed their heavy participations in the organization of communication blocks, especially in routes involving inter-hemispheric heterotopic and extremely remote intra-hemispheric systems. Computational simulation models indicated the sharp decrease of global network integrity when attacking these highly centralized edges. Together, our results demonstrated high building-cost consumption and substantial communication capacity contributions for pivotal WM connections, which deepens our understanding of the topological mechanisms that govern the organization of human connectomes.

No MeSH data available.