These days I am manually editing some data and this subject is giving me such a hard time. In fact I would like the near-to-cortexartefacts at the top right hand corner to be excluded from the surface but even after changing the intensity of the wanted part to 255 and the one of the excluded parts to 1 (which is nevertheless not visible on these images) the surface is still not what I would like it to become. In adition to editing the wm.mgz file, I also modified the aseg.presurf file to exclude these parts and I re-runned the -normalization2 and -maskbfs flags to generate new brain.mgz and brain.finalsurfs.mgz files.