English: Boxplot of the peak of significance value (arbitrary unit) for each participant in both groups, as obtained by SPM5 ‘fitted response’ plot function. Peak value was adjusted, meaning that the effect of age, gender and global WM volume were factored out, and only the effect of condition (Parkinson or Control) and the residuals remained, as assessed by the SPM model. For each group, bold line shows the median, central box includes the middle 50% of the data, and tails of the boxplot show the minimum and maximum values.