Disrupted Topological Organization of Resting‐State Functional Brain Network in Subcortical Vascular Mild Cognitive Impairment

Summary Aims Neuroimaging studies have demonstrated both structural and functional abnormalities in widespread brain regions in patients with subcortical vascular mild cognitive impairment (sv MCI ). However, whether and how these changes alter functional brain network organization remains largely unknown. Methods We recruited 21 patients with sv MCI and 26 healthy control ( HC ) subjects who underwent resting‐state functional magnetic resonance imaging scans. Graph theory‐based network analyses were used to investigate alterations in the topological organization of functional brain networks. Results Compared with the HC individuals, the patients with sv MCI showed disrupted global network topology with significantly increased path length and modularity. Modular structure was also impaired in the sv MCI patients with a notable rearrangement of the executive control module, where the parietal regions were split out and grouped as a separate module. The sv MCI patients also revealed deficits in the intra‐ and/or intermodule connectivity of several brain regions. Specifically, the within‐module degree was decreased in the middle cingulate gyrus while it was increased in the left anterior insula, medial prefrontal cortex and cuneus. Additionally, increased intermodule connectivity was observed in the inferior and superior parietal gyrus, which was associated with worse cognitive performance in the sv MCI patients. Conclusion Together, our results indicate that sv MCI patients exhibit dysregulation of the topological organization of functional brain networks, which has important implications for understanding the pathophysiological mechanism of sv MCI .