Fig. 4

Disease-specific patterns (arbitrary units) for ALS (1) and PP (2) determined by PCA-LR (a), PCA-SVM (b), and SVM (c). The values in each voxel represent the weights of the contribution of the voxel for the classifier. Positive values (red) indicate regions of hypermetabolism of ALS or PP patients compared to HC whereas negative values (blue) correspond to hypometabolism of ALS or PP patients compared to HC