Build ROI with all voxels of an atlas


I want to build a ROI with all the voxels of the atlas (in my case the Glasser atlas). Is there a shortcut how to do this or do I need to put the indexes of each ROI?

Thanks a lot

You want the whole brain? Atlas regions are values above 0. So you could do:

3dcalc -a atlas+tlrc -expr 'step(a)' -prefix myWholeROI