Dear freesurfers, I want to look at the gender differences of a correlation between cortical thickness and some impulsivity-tests. When I use qdec, the question "Does the thickness-BIS-correlation differ between 0 and 1?" is displayed. So, 0 and 1 are female/male. But there are positive and negative correlations (red and blue voxels)...what does it mean? There can not be a negative difference...?? Thank you very much! Leni