Functional Brain Networks Are Altered In Type 2 Diabetes And Correlation With Cognitive Function

Objective: This study investigated whether functional brain networks are affected in T2DM patients with mild cognitive impairment and T2DM patients without cognitive impairment.Materials and Methods: This study recruited T2DM patients with mild cognitive impairment(n=15,8 males and 7 females),T2DM patients without mild cognitive impairment(n=14,9 males and 5 females)and healthy control subjects(n=17,12 males and 5 females)to undergo cognitive testing and resting-state functional magnetic resonance imaging.Graph theoretical network analysis was performed to investigate alterations in functional cerebral networks.This study constructed the whole-brain network with the automated anatomical labeling(AAL)atlas.The whole-brain functional connectome was constructed by applying a threshold to the resultant 90 × 90 correlation matrix.To locate the specific pairs of region showing altered functional connectivity,this study performed the network-based connections(NBS)method.Used partial correlation analyses with age,gender and education as confounding factors to assess the relationships between the abnormal network connectivity and the Mo CA scores.Results: Graph theoretical analysis of functional brain networks revealed small-world architecture in T2DM patients with mild cognitive impairment,T2DM patients without cognitive impairment and control subjects.The functional brain networks of T2DM patients with mild cognitive impairment and T2DM patients without cognitive impairment showed similar global network metrics to those in healthy controls.Compare with healthy controls,reduced nodal characteristics were distributed in the frontal and occipital lobes,while increased nodal characteristics were distributed in the frontal lobes and parietal lobes in the T2DM patients with mild cognitive impairment.Reduced nodal characteristics were distributed in the frontal lobes and occipital lobes,while increased nodal characteristics were distributed in the frontal lobes,parietal lobes and temporal lobes in the T2DM patients without cognitive impairment compare with healthy controls.Moreover,comparison between T2DM patients with mild cognitive impairment and T2DM patients without cognitive impairment,mainly in the frontal lobe local brain area node characteristics have changed.NBS analysis identified 33 altered connections between the T2DM patients with mild cognitive impairment and control subjects.And there are 6 altered connections between the T2DM patients without cognitive impairment and control subjects.These findings demonstrate altered topological organization of functional brain networks in T2DM patients without mild cognitive impairment and T2DM patients without cognitive impairment.In addition,the T2DM patients with mild cognitive impairment showed disrupted network topological properties related to Mo CA.Conclusion: These findings demonstrate altered topological organization of functional brain networks in T2DM patients without mild cognitive impairment.Moreover,this study showed that graph theory-based network analysis could identify the nature of the cerebral changes underlying the diabetes related cognitive decline.