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Fragmentation: loss of global coherence or breakdown of modularity in functional brain architecture?

Psychiatric illnesses characterized by disorganized cognition, such as schizophrenia, have been described in terms of fragmentation and hence understood as reduction in functional brain connectivity, particularly in prefrontal and parietal areas. However, as graph theory shows, relatively small numb...

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Autores principales: van den Berg, Daan, Gong, Pulin, Breakspear, Michael, van Leeuwen, Cees
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3316147/
https://www.ncbi.nlm.nih.gov/pubmed/22479239
http://dx.doi.org/10.3389/fnsys.2012.00020
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author van den Berg, Daan
Gong, Pulin
Breakspear, Michael
van Leeuwen, Cees
author_facet van den Berg, Daan
Gong, Pulin
Breakspear, Michael
van Leeuwen, Cees
author_sort van den Berg, Daan
collection PubMed
description Psychiatric illnesses characterized by disorganized cognition, such as schizophrenia, have been described in terms of fragmentation and hence understood as reduction in functional brain connectivity, particularly in prefrontal and parietal areas. However, as graph theory shows, relatively small numbers of nonlocal connections are sufficient to ensure global coherence in the modular small-world network structure of the brain. We reconsider fragmentation in this perspective. Computational studies have shown that for a given level of connectivity in a model of coupled nonlinear oscillators, modular small-world networks evolve from an initially random organization. Here we demonstrate that with decreasing connectivity, the probability of evolving into a modular small-world network breaks down at a critical point, which scales to the percolation function of random networks with a universal exponent of α = 1.17. Thus, according to the model, local modularity systematically breaks down before there is loss of global coherence in network connectivity. We, therefore, propose that fragmentation may involve, at least in its initial stages, the inability of a dynamically evolving network to sustain a modular small-world structure. The result is in a shift in the balance in schizophrenia from local to global functional connectivity.
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spelling pubmed-33161472012-04-04 Fragmentation: loss of global coherence or breakdown of modularity in functional brain architecture? van den Berg, Daan Gong, Pulin Breakspear, Michael van Leeuwen, Cees Front Syst Neurosci Neuroscience Psychiatric illnesses characterized by disorganized cognition, such as schizophrenia, have been described in terms of fragmentation and hence understood as reduction in functional brain connectivity, particularly in prefrontal and parietal areas. However, as graph theory shows, relatively small numbers of nonlocal connections are sufficient to ensure global coherence in the modular small-world network structure of the brain. We reconsider fragmentation in this perspective. Computational studies have shown that for a given level of connectivity in a model of coupled nonlinear oscillators, modular small-world networks evolve from an initially random organization. Here we demonstrate that with decreasing connectivity, the probability of evolving into a modular small-world network breaks down at a critical point, which scales to the percolation function of random networks with a universal exponent of α = 1.17. Thus, according to the model, local modularity systematically breaks down before there is loss of global coherence in network connectivity. We, therefore, propose that fragmentation may involve, at least in its initial stages, the inability of a dynamically evolving network to sustain a modular small-world structure. The result is in a shift in the balance in schizophrenia from local to global functional connectivity. Frontiers Media S.A. 2012-03-30 /pmc/articles/PMC3316147/ /pubmed/22479239 http://dx.doi.org/10.3389/fnsys.2012.00020 Text en Copyright © 2012 van den Berg, Gong, Breakspear and van Leeuwen. http://www.frontiersin.org/licenseagreement This is an open-access article distributed under the terms of the Creative Commons Attribution Non Commercial License, which permits non-commercial use, distribution, and reproduction in other forums, provided the original authors and source are credited.
spellingShingle Neuroscience
van den Berg, Daan
Gong, Pulin
Breakspear, Michael
van Leeuwen, Cees
Fragmentation: loss of global coherence or breakdown of modularity in functional brain architecture?
title Fragmentation: loss of global coherence or breakdown of modularity in functional brain architecture?
title_full Fragmentation: loss of global coherence or breakdown of modularity in functional brain architecture?
title_fullStr Fragmentation: loss of global coherence or breakdown of modularity in functional brain architecture?
title_full_unstemmed Fragmentation: loss of global coherence or breakdown of modularity in functional brain architecture?
title_short Fragmentation: loss of global coherence or breakdown of modularity in functional brain architecture?
title_sort fragmentation: loss of global coherence or breakdown of modularity in functional brain architecture?
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3316147/
https://www.ncbi.nlm.nih.gov/pubmed/22479239
http://dx.doi.org/10.3389/fnsys.2012.00020
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