Neural Correlates and Adaptive Mechanisms in Vascular Cognitive Impairment: Exploration of a Structure–Function Coupling Network

Cerebral small vessel disease exacerbates cognitive decline, yet the structural-functional coupling mechanisms in vascular cognitive impairment (VCI) remain unclear. This study included 121 participants, with 68 individuals with VCI and 53 healthy controls. Participants underwent neuropsychological assessments and multimodal imaging. We compared white matter integrity, structural network topology, and functional network topology between groups, exploring the relationship between structure-function coupling and cognitive function. Family-wise error (FWE) correction was applied to account for multiple comparisons. VCI participants showed reduced fractional anisotropy and increased mean and radial diffusivity in white matter. Structural network analysis revealed lower global and local efficiency, reduced small-world properties, and increased characteristic path length. Nodal properties, particularly in key regions of the default mode and visual networks, were significantly altered in VCI participants. While no significant differences were observed in functional network topology, VCI participants exhibited enhanced structure-function coupling in critical nodes of the default mode and visual networks. This enhancement correlated with memory function and information processing speed in the temporal calcarine, insula, occipital, and lingual regions. The study identifies disrupted brain networks and enhanced compensatory mechanisms in VCI, offering insights into neuroplasticity in VCI and contributing to dementia prevention strategies.