Altered Resting-State Co-Activation Patterns in Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) has been associated with abnormal large-scale brain network dynamics, but its transient whole-brain co-activation states remain insufficiently characterized. Against this background, the current study investigated potential alterations in the dynamics of whole-brain co-activation pattern (CAP) in OCD.

Resting-state functional magnetic resonance imaging (rs-fMRI) data were parcellated using the Brainnetome 246 atlas and analyzed with a CAP framework. CAP states were identified with k-means clustering, and temporal fraction, persistence, counts, and transition probabilities were compared between OCD and healthy controls.

Three recurrent CAP states were identified as the optimal clustering solution. CAP2 showed a distinct intermediate bipolar configuration, with positive weights mainly involving thalamic, inferior frontal, medial temporal, temporoparietal, and medial superior frontal regions and negative weights mainly involving auditory, primary sensorimotor and dorsal insular regions. Yeo-7 mapping further showed that CAP2 had positive weights in the default mode and negative weights in the somatomotor systems. Compared with healthy controls, patients with OCD showed increased CAP2 temporal fraction, persistence, and self-transition probability, together with reduced counts and reduced transition probabilities from CAP2 to both CAP1 and CAP3.

These findings suggest that OCD is associated with reduced switching flexibility and an increased tendency to stay in a specific brain state configuration across time.