Time dependent SOM proteomics portraits of urine samples taken before, during and after the isolation experiment (panel a) and time trajectory as obtained using 2nd level SOM mapping (panel b). The results refer to the 'mean-volunteer analysis' by averaging the proteomics data over the six volunteers at each time point. Each column of images in panel a refers to one cluster as determined using 2nd level SOM similarity analysis shown in panel b. Thin arrows indicate the temporal order of the specimen and thus the trajectory of the urine proteomics samples. The amount a salt consumption per volunteer and day during the isolation experiment is indicated in the figures: the arrows indicate the times of changing salt consumption. The dashed lines divide the trajectory into early, intermediate and late time ranges. The 'early' time-regime further subdivides into two clusters of samples collected before and after start of the isolation experiment (ellipses). Alternative independent component analysis of the sample trajectory is given in the supplementary text (Additional file 1).