Hello SPM experts,
I am setting up a flexible factorial design with a library of PET scans and have chosen global normalisation as one of my options, with overall grand mean scaling. When my model design is outputted by SPM, it includes a column titled "global", and most of scans are represented different shades of gray. However, for one of my subjects, all of the scans are black, could anybody tell me what this might represent?
Wayne State University