Altered local gyrification index and corresponding functional connectivity in Alzheimer disease

Abstract

AbstractBackgroundCortical gyrification is a promising surface anatomical marker to study Alzheimer disease, however, few studies combined the gyrification and functional connectivity together to explore the Potential mechanism in Alzheimer disease.MethodThe study consisted of three groups, healthy control(n=37), Mild cognitive impairment(n=39), and Alzheimer disease(n=30). Comparison between groups of gyrification was performed using ANOVA within CAT12 and SPM 12, age and cortical thickness were returned as covariates. After the LGI analyses, the surface areas with changed LGI were taken as seed regions for functional connectivity (FC) analyses. Comparison between groups of FCs was performed using ANOVA within dpabi 4.3 and RESTplus; age was returned as a covariate. False discovery rate (FDR)‐corrected and P < 0.05 was considered statistically significant.ResultCompared with NC and MCI group, we found significantly decreased LGI(local gyrification index) in left insula and right insula, and the changed LGI in bilateral insula was negatively correlated with disease onset age and positively correlated with global cognitive scores. The following functional connectivity analyses identified decreased functional connectivity between right insula and middle temporal gyrus. The decreased functional connectivities were correlated with disease duration, and global cognitive scores.ConclusionOur findings revealed abnormal LGI in bilateral insula and the connectivity between right insula and middle temporal gyrus maybe used as imaging metrics of Alzheimer disease.