Dysregulated connectivity configuration of triple-network model in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is signified by altered functional network connectivity (FNC), particularly within the default mode network (DMN), salience network (SAL), and fronto-parietal network (FPN). While previous studies suggest disruptions within triple networks, dynamic causal interactions across networks remain unaddressed. This study seeks to validate previous findings of static dysconnectivity between triple networks and further delineate the time-varying interactions and causal relationships among these networks in OCD. A resting-state functional magnetic resonance imaging study was performed on a relatively large and well-characterized clinical sample, comprising 88 medication-free OCD patients and 93 healthy controls (HC). Group independent component analysis, combined with a sliding window approach and k-means clustering analysis, was used to assess static and dynamic time-varying FNC within triple networks. Spectral dynamic causal modelling and parametric empirical Bayes framework were utilized to explore the abnormal effective connectivity among these networks in OCD patients. Our results proposed a novel dysregulated connectivity configuration of the triple-network model for OCD. With the self-inhibition increase in the left FPN, the excitatory effect onto the right FPN decrease, resulting in a weakened static connectivity between the left and right FPNs. Concurrently, time-varying hypoconnectivity patterns are observed between the left FPN and DMN, as well as the right FPN and SAL in OCD. Additionally, the excitatory influence from the DMN to the SAL suggests an atypical modulation within OCD's network pathology. These findings advance our understanding of the dysregulated information transfer and the complex interplay of brain networks in OCD, potentially guiding future therapeutic strategies.