I have a question related to this topic. I would like to create figures similar to those produced by "Display as image", but I would like to use a parameter to sort files/subjects (equivalent to EEGlab's "EEG image"). Rather than adding tags to filenames, I would like to add fields to the data structure. For example, a "Behavioral" field with subfields like "RT" and "ACC" etc. I realize this approach wouldn't work with the file grouping processes or the GUI filter, but I'm wondering if Brainstorm will delete unrecognized fields added to each files underlying Matlab structure variable.