We conducted multivariate analyses using canonical correlation analysis (CCA32) combined with independent component analysis (ICA33) (see Figs 7-8, Supplementary Figs 3-7 and Online Methods). This analysis identifies “modes” of population covariation linking IDPs to non-imaging measures. Each mode consists of one linear combination of IDPs and a separate combination of non-imaging measures that have a highly similar variation across subjects. The strength of involvement of a variable in a given mode is dictated by the variable weight (Fig 7). Multiple population modes may be identified, provided they describe different (independent) cross-subject variation, meaning that the implied association between a given pair of variables can vary from mode to mode.
