Altered topological properties in white matter structural networks in patients with schizophrenia

Abstract

Objective To explore the changes of whole brain white matter (WM) structural network topological property in patients with schizophrenia (SP) and the associations between WM networks topological efficiency and clinical variables in patients. Methods Deterministic tractography was used to construct the WM networks of 59 patients with SP (patients group) and 41 age-, handedness-, and gender-matched healthy controls (HCs), and graph theoretical methods were applied to investigate abnormalities in the global and nodal properties of the WM network in these patients.Partial correlation analysis was used to analyze the relationship between global and nodal properties of the WM network and clinical variables in patients with SP. Results Both the patients with SP and HCs showed small-world organization of the WM networks.However, compared with HCs, the patients with SP exhibited significant abnormal global topology, including increased shortest path length (t=7.95, P=0.0001) and decreased global efficiency (30.83±16.08, 8.25±6.13, t=-9.81, P=0.002), clustering coefficiency (0.03±0.01, 0.02±0.01, t=-4.48, P=0.0003), the average clustering coefficiency (t=-8.28, P=0.002), the small-worldness (3.92±0.79, 2.79±0.56, t=-7.82, P=0.001) of their WM structural networks(all P<0.005, FDR corrected). Further, the patients with SP showed a reduction in nodal efficiency predominately in the cingulate gyrus (t=-4.11, P=0.000), superior occipital gyrus (t=-6.05, P=0.002), superior temporal gyrus (t=-10.46, P=0.001), middle temporal gyrus (t=-10.38, P=0.000), thalamus (t=-6.10, P=0.000) and putamen (t=-8.38, P=0.000) (P<0.005, FDR corrected). Partial correlation results showed that there was no significant correlation between global topological properties, node efficiency and clinical symptoms in patients group(Eglob: r=-0.14, P=0.279; Eloc: r=-0.06, P=0.628; Lp: r=0.28, P=0.031; Cp: r=0.27, P=0.043; λ: r=-0.18, P=0.166; γ: r=-0.29, P=0.026; σ: r=0.26, P=0.048; nEglob: r=0.36, P=0.005; nEloc: r=0.02, P=0.901). Conclusions The patients with SP exhibit the abnormal of whole brain WM structural network topological property and the node efficiencies of cortico-striato-thalamo circuitry are significantly reduced. Key words: Schizophrenia; White matter; Topological properties; Graph theoretical