title: Different alterations in brain functional networks according to direct and indirect topological connections in patients with schizophrenia.
abstract: Schizophrenia displays connectivity deficits in the brain, but the literature has shown inconsistent findings about alterations in global efficiency of brain functional networks. We supposed that such inconsistency at the whole brain level may be due to a mixture of different portions of global efficiency at sub-brain levels. Accordingly, we considered measuring portions of global efficiency in two aspects: spatial portions by considering sub-brain networks and topological portions by considering contributions to global efficiency according to direct and indirect topological connections. We proposed adjacency and indirect adjacency as new network parameters attributable to direct and indirect topological connections, respectively, and applied them to graph-theoretical analysis of brain functional networks constructed from resting state fMRI data of 22 patients with schizophrenia and 22 healthy controls. Group differences in the network parameters were observed not for whole brain and hemispheric networks, but for regional networks. Alterations in adjacency and indirect adjacency were in opposite directions, such that adjacency increased, but indirect adjacency decreased in patients with schizophrenia. Furthermore, over connections in frontal and parietal regions, increased adjacency was associated with more severe negative symptoms, while decreased adjacency was associated with more severe positive symptoms of schizophrenia. This finding indicates that connectivity deficits associated with positive and negative symptoms of schizophrenia may involve topologically different paths in the brain. In patients with schizophrenia, although changes in global efficiency may not be clearly shown, different alterations in brain functional networks according to direct and indirect topological connections could be revealed at the regional level.
authors.affiliation: Ewha Brain Institute, Ewha Womans University, Seoul, Republic of Korea.
authors.forename: Chang-Hyun
authors.initials: CH
authors.lastname: Park
authors.affiliation: Department of Psychiatry, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Seungyup
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Psychiatry, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Republic of Korea.
authors.forename: Taewon
authors.initials: T
authors.lastname: Kim
authors.affiliation: Department of Psychiatry, St. Paul's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Wang Yeon
authors.initials: WY
authors.lastname: Won
authors.affiliation: Department of Psychiatry, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea. Electronic address: mindcure@catholic.ac.kr.
authors.forename: Kyoung-Uk
authors.initials: KU
authors.lastname: Lee
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000503:physiopathology; D011569:Psychiatric Status Rating Scales; D012146:Rest; D012559:Schizophrenia / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology*; D012720:Severity of Illness Index
chemical_list: D014150:Antipsychotic Agents
keywords: Adjacency; Efficiency; Graph-theoretical analysis; Indirect adjacency; Schizophrenia; fMRI