RESUMEN
Objective To investigate the influence of type 2 diabetes mellitus(T2DM)on cognitive function and the effective connectivity with in the default mode network(DMN)in the brain.Methods A total of 93 hospitalized patients diagnosed with T2DM were enrolled in this study as T2DM group from The First Affiliated Hospital of Guangzhou University of Chinese Medicine during September 2021 to December 2022.Simultaneously,108 healthy individuals were recruited from the community as normal control(NC)group.The cognitive functions were evaluated in the two groups.A random dynamic causal modeling approach was employed to analyze the effective connectivity within DMN in both groups.Additionally,Pearson correlation analysis was performed to examine the association between differential connectivity,clinical indicators,and cognitive scores in both groups.Results In comparison to the NC group,T2DM individuals exhibited statistically significant reductions in scores in the auditory verbal learning test(AVLT)for immediate recall and the digit symbol substitution test(DSST)(P＜0.05).Additionally,they displayed a notable decrease in effective connectivity from the left lateral parietal cortex(LLPC)to the posterior cingulate cortex(PCC),as well as from the LLPC to the right lateral parietal cortex(RLPC)within the DMN(P＜0.05).Pearson correlation analysis unveiled a negative association between HbA1c levels and the strength of effective connectivity from LLPC to PCC.Conversely,a positive correlation was observed between AVLT(immediate)scores and the strength of effective connectivity from LLPC to PCC and LLPC to RLPC.Additionally,DSST scores displayed a positive correlation with the strength of effective connectivity from LLPC to PCC(P＜0.05).Conclusion Patients with T2DM display compromised effective connectivity from LLPC to PCC and LLPC to RLPC within the DMN network,and this alteration may associated with cognitive impairment.