Analysis of changes in grey-white matter contrast in healthy older adults

Abstract

Gray-white matter contrast (GWC) is a valuable proxy for brain health. In this study, we analyzed regional changes in GWC using structural MRI data from the UK Biobank, collected between 2006 and 2019. Leveraging the Desikan-Killiany (DK) Freesurfer brain atlas, we identified two groups: “Contrast Gainers” and “Contrast Decliners”. For each group, we computed Pearson correlations between GWC changes across brain regions and used Jennrich’s test to assess statistical differences in correlation structures. Results showed that the correlation matrices corresponding to Contrast Gainers and Contrast Decliners were substantially different. To enhance interpretability, we employed hierarchically reordered heatmaps and network diagrams. The heatmaps revealed clusters of strongly correlated brain regions in both groups, while the network diagrams highlighted similarities and differences in regional patterns. Our analysis uncovers statistically significant differences in GWC correlation patterns between Contrast Gainers and Decliners, suggesting potential applications in understanding neurodegenerative processes and brain aging.