The 500,000 UK Biobank participants were recruited from across Great Britain. All participants provided informed consent. The present analyses were conducted under UK Biobank application number 25163. Further information on the consent procedure can be found here (biobank.ctsu.ox.ac.uk/crystal/field.cgi?id=200). Our study involved brain imaging from 10,129 individuals, 47.6% males and 52.4% females, aged 40 y to 69 y, to detail the neurobiological properties of the DMN by means of T1-weighted MRI (sMRI), dMRI, and resting-state functional MRI (fMRI). Jointly analyzing gray matter volume (sMRI) and white matter microstructure (dMRI) allowed testing whether interindividual differences in DMN volume are linked to variability in fiber bundle microstructure. The DMN subregion volumes of each subject provided the input data for pattern learning analyses based on maximum−margin linear SVR to assess predictability of water diffusion characteristics of 48 white matter tracts. Functional connectivity measures among DMN subregions were derived by computing the partial correlations between their neural activity fluctuations (fMRI), guided by the DMN atlas. Topographical definitions of 21 common large-scale networks were used with the network analysis tool from FSL (FSLNets) to compute partial correlations between every pair of networks.
