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Pharmacopsychiatry 2012; 45(S 01): S57-S64
DOI: 10.1055/s-0032-1309001
Original Paper
© Georg Thieme Verlag KG Stuttgart · New York

Functional Graph Alterations in Schizophrenia: A Result from a Global Anatomic Decoupling?

J. Cabral
1   Theoretical and Computational Neuroscience Group, Center for Brain and Cognition, Universitat Pompeu Fabra, Barcelona, Spain
2   Department of Psychiatry, University of Oxford, Oxford, U.K.
,
M. L. Kringelbach
2   Department of Psychiatry, University of Oxford, Oxford, U.K.
3   Center of Functionally Integrative Neuroscience (CFIN), Aarhus University, Aarhus, Denmark
,
G. Deco
1   Theoretical and Computational Neuroscience Group, Center for Brain and Cognition, Universitat Pompeu Fabra, Barcelona, Spain
4   Institut Català de Recerca i Estudis Avançats, Barcelona, Spain
› Author Affiliations
Further Information

Publication History

Publication Date:
07 May 2012 (online)

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Abstract

Introduction:

During rest, the brain exhibits slow hemodynamic fluctuations (<0.1 Hz) that are correlated across spatially segregated brain regions, defining functional networks. Resting-state functional networks of people with schizophrenia were found to have graph properties that differ from those of control subjects. Namely, functional graphs from patients exhibit reduced small-worldness, increased hierarchy, lower clustering, improved efficiency and greater robustness. Notably, most of these parameters correlate with patients’ cognitive performance.

Methods:

To test if a brain-wide coupling deficit could be at the origin of such network reorganization, we use a model of resting-state activity where the coupling strength can be manipulated. For a range of coupling values, the simulated functional graphs obtained were characterized using graph theory.

Results:

For a coupling range, simulated graphs shared properties of healthy resting-state functional graphs. On decreasing the coupling strength, the resultant functional graphs exhibited a topological reorganization, in the same way as described in schizophrenia.

Discussion:

This work shows how complex functional graph alterations reported in schizophrenia can be accounted for by a decrease in the structural coupling strength. These results are corroborated by reports of lower white matter density in schizophrenia.

Key words

computational model - structural connectivity - functional network - graph theory - schizophrenia
 

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