Altered controllability of functional brain networks in obsessive-compulsive disorder.

Disruptions in the dynamic transitions between brain states have been implicated in cognitive, emotional, and behavioral dysregulations across various mental disorders. However, the irregularities in dynamic brain state transitions associated with obsessive-compulsive disorder (OCD) remain unclear. The present study included 99 patients with OCD and 104 matched healthy controls (HCs) to investigate alterations in dynamic brain state transitions by using network control theory. Functional controllability metrics were computed and compared between the OCD group and HCs. Additionally, abnormal functional connectivity (FC) between the brain regions with statistical differences in functional controllability and remaining brain regions were assessed. Patients with OCD exhibited significantly decreased average controllability (AC) and increased modal controllability (MC) in the right parahippocampal gyrus (PHG), compared to the HCs. Further analysis showed significantly decreased FC between the right PHG and bilateral superior temporal gyrus and occipital gyrus, left postcentral gyrus, and right cingulate gyrus in OCD patients. The results suggest aberrant brain state transitions in OCD patients, alongside widespread disruptions within the brain functional connectome. This study highlights the critical role of altered functional controllability within the right PHG in the neuropathological mechanisms of OCD, providing novel insights into the pathogenesis of OCD.