Hi Ziad,

So I tried to create a mask using your formula but for some reason when I try to load it into SUMA to verify that the mask does contain the two regions, the mask is empty. I don't see anything on the surface. Also, I ran 3dinfo on the file and here is the output:

[Izzo@isabelle-deschampss-macbook-pro.local: Sun Jun 3 11:52:19 2012] ===================================
[Izzo@isabelle-deschampss-macbook-pro.local: Sun Jun 3 11:52:19 2012] === History of inputs to 3dcalc ===
[Izzo@isabelle-deschampss-macbook-pro.local: Sun Jun 3 11:52:19 2012] === Input a:
[Izzo@isabelle-deschampss-macbook-pro.local: Sun Jun 3 11:52:19 2012] === Input b:
[Izzo@isabelle-deschampss-macbook-pro.local: Sun Jun 3 11:52:19 2012] ===================================
[Izzo@isabelle-deschampss-macbook-pro.local: Sun Jun 3 11:52:19 2012] 3dcalc -a 'norm.lh.aparc.a2009s.annot.niml.dset<wm_lh_G_pariet_inf-Supramar>' -b 'norm.lh.aparc.a2009s.annot.niml.dset<wm_lh_G_front_inf-Triangul>' -expr 'step(a)+2*step(b)' -prefix try.lh.from_annot.gii.dset;


Here is the command I ran:

cd /Volumes/HUNTER/SUBJECTS_DIR/S001/SUMA/

set zone1 = wm_lh_G_pariet_inf-Supramar
set zone2 = wm_lh_G_front_inf-Triangul
3dcalc -a norm.lh.aparc.a2009s.annot.niml.dset"<$zone1>" -b norm.lh.aparc.a2009s.annot.niml.dset"<$zone2>" -expr 'step(a)+2*step(b)' -overwrite -prefix try.lh.from_annot.gii.dset

I also tried without the wm_lh in front of the names but same thing happens.

Thanks again for your help,

Isabelle