Hi Tobias, As far as I understand, when you run the 'cg_vbm_optimized.m' batch, you are asked about the output of your script. You should use the GUI to select 'gray matter' 'gray+white matter' or 'all' depending on which choice you are interested. I hope this helps, Gracián. _______________________________________________ Gracián García | [log in to unmask] BET (Bioingeniería, Electrónica y Telemedicina) Universidad Politécnica de Valencia. _______________________________________________