Figure 4.

Principal component analysis of all data. Panel (a): the projections of the variables into the space of the first three PCs, showing which PCs are dominated by which variables. The variables are labelled by WM tract and coloured by variable type (see legend). Only if the projection in to the space of the first four PCs was large (see methods) are the variables displayed. Panel (b): contributions to the PC1-4 by all variables (PCA coefficients). The distinct types of variables are coloured as in panel (a) and separated by the dotted lines.