Disrupted functional connectivity of precuneus subregions in obsessive-compulsive disorder.

Obsessive-compulsive disorder (OCD) is a chronic and disablingpsychiatric disorder with high lifetime prevalence, yet the underlying pathogenesis remains not fully understood. Increasing neuroimaging evidence has shown that the disrupted activity of brain functional hubs might contribute to the pathophysiology of OCD. Precuneus is an important brain hub which showed structural and functional abnormalities in OCD patients. However, the functional heterogeneity of the precuneus subregion has not been considered and its relation to OCD symptomatology remains to be elucidated. In this paper, a total of 73 unmedicated OCD patients and 79 matched healthy subjects were recruited and the heterogeneous functional connectivities (FCs) of the precuneus subregions were investigated using resting-state functional magnetic resonance imaging. The FC-based subdivision of the precuneus was performed using the K-means clustering algorithm, which led to a tripartite functional parcellation of precuneus. For each subregion, the distinct connectivity pattern with the whole brain was shown, using both voxel-wise and module-wise analysis, respectively. Decreased FC between dorsal posterior precuneus and vermis (corrected p<0.01) was shown in the patient group, which was negatively correlated with patient compulsions score (ρ = - 0.393, p = 0.001), indicating its contribution to the compulsive behavior inhibition of OCD. Our work might provide new insights into the understanding of precuneus subregion function and the importance of dorsal precuneus-cerebellum functional connectivity in OCD pathophysiology.