title: Disrupted small-world networks in schizophrenia.
abstract: The human brain has been described as a large, sparse, complex network characterized by efficient small-world properties, which assure that the brain generates and integrates information with high efficiency. Many previous neuroimaging studies have provided consistent evidence of 'dysfunctional connectivity' among the brain regions in schizophrenia; however, little is known about whether or not this dysfunctional connectivity causes disruption of the topological properties of brain functional networks. To this end, we investigated the topological properties of human brain functional networks derived from resting-state functional magnetic resonance imaging (fMRI). Data was obtained from 31 schizophrenia patients and 31 healthy subjects; then functional connectivity between 90 cortical and sub-cortical regions was estimated by partial correlation analysis and thresholded to construct a set of undirected graphs. Our findings demonstrated that the brain functional networks had efficient small-world properties in the healthy subjects; whereas these properties were disrupted in the patients with schizophrenia. Brain functional networks have efficient small-world properties which support efficient parallel information transfer at a relatively low cost. More importantly, in patients with schizophrenia the small-world topological properties are significantly altered in many brain regions in the prefrontal, parietal and temporal lobes. These findings are consistent with a hypothesis of dysfunctional integration of the brain in this illness. Specifically, we found that these altered topological measurements correlate with illness duration in schizophrenia. Detection and estimation of these alterations could prove helpful for understanding the pathophysiological mechanism as well as for evaluation of the severity of schizophrenia.
authors.affiliation: National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Liu
authors.forename: Meng
authors.initials: M
authors.lastname: Liang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Yong
authors.initials: Y
authors.lastname: He
authors.forename: Yihui
authors.initials: Y
authors.lastname: Hao
authors.forename: Ming
authors.initials: M
authors.lastname: Song
authors.forename: Chunshui
authors.initials: C
authors.lastname: Yu
authors.forename: Haihong
authors.initials: H
authors.lastname: Liu
authors.forename: Zhening
authors.initials: Z
authors.lastname: Liu
authors.forename: Tianzi
authors.initials: T
authors.lastname: Jiang
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging; D008297:Male; D008959:Models, Neurological; D009434:Neural Pathways / Q000503:physiopathology; D012559:Schizophrenia / Q000473:pathology / Q000503:physiopathology*; D013997:Time Factors