Brain Functional Network Study Of Obsessive-Compulsive Disorder Patients Using Magnetic Resonance Imaging

Obsessive-compulsive disorder(OCD)is a chronic and potentially disabling anxiety disorder with high lifetime prevalence rate,yet the underlying pathogenesis remains not fully understood.Increasing neuroimaging evidence has shown that the disrupted activity of brain functional networks and brain functional hubs might contribute to the pathophysiology of OCD.The aim of this study is to investigate the alteration of large-scale brain networks and metabolic/functional changes of brain functional hubs in OCD patients.In this study,resting-state functional magnetic resonance imaging(rs-fMRI)and proton magnetic resonance spectroscopy(~1H-MRS)technologies were applied for image data acquisition.We estimated the whole-brain modular properties and metabolites concentrations in anterior insula(AI)of forty drug-nai?ve and forty-one medicated OCD patients and 81 well-matched healthy controls.We investigated the functional connectivity strength(FCS)and heterogeneous functional connectivities of precuneus(PCu)subregions of 73 unmedicated OCD patients with 79 matched healthy subjects.Two sample t tests were used to assess the group differences of modular property,functional connectivity and metabolic concentration.Finally,their relationships with OCD symptomatology were also investigated by correlation analysis.Our results showed a wide range of modular functional alterations in OCD patients,with or without medication.Interestingly,medicated OCD patents showed a more similar network connectivity pattern with healthy controls.Medicated OCD has a relatively high glutamate metabolic level in right AI and was positively correlated with the inter-modular connection between the visual network and the default mode network.Significantly higher FCS of PCu was shown,indicating its role as a functional hub.We also found increased FCS in precentral and postcentral gyrus within sensor-motor network and decreased FCS in insula within salience network.Functional connection between insula and the inferior frontal gyrus was negatively correlated with metabolic level of glutamate and N-acetylaspartate in the left AI.Finally,the analysis of PCu subregions showed the dorsal precuneus-cerebellum functional disruptions in OCD.Our study suggested that the atypical functional network connectivity and metabolic changes and functional alterations of the brain functional hubs might be important neurobiological mechanism of OCD,which may be affected by drug effects.Our findings demonstrate the feasibility of understanding the pathophysiology of OCD from the perspective of functional brain networks.