1 research outputs found
Resilience of human brain functional coactivation networks under thresholding
Recent studies have demonstrated the existence of community structure and
rich club nodes, (i.e., highly interconnected, high degree hub nodes), in human
brain functional networks. The cognitive relevance of the detected modules and
hubs has also been demonstrated, for both task based and default mode networks,
suggesting that the brain self-organizes into patterns of co-activated sets of
regions for performing specific tasks or in resting state. In this paper, we
report studies on the resilience or robustness of this modular structure: under
systematic erosion of connectivity in the network under thresholding, how
resilient is the modularity and hub structure? The results show that the
network shows show strong resilience properties, with the modularity and hub
structure maintaining itself over a large range of connection strengths. Then,
at a certain critical threshold that falls very close to 0, the connectivity,
the modularity, and hub structure suddenly break down, showing a phase
transition like property. Additionally, the spatial and topological
organization of erosion of connectivity at all levels was found to be
homogenous rather than heterogenous; i.e., no "structural holes" of any
significant sizes were found, and no gradual increases in numbers of components
were detected. Any loss of connectivity is homogenously spread out across the
network. The results suggest that human task-based functional brain networks
are very resilient, where the whole network structure fails only when
connectivity is almost fully removed from the network. The findings may help
further the understanding of dynamics of and relationships between structural
and functional brain networks.Comment: 8 page