-12-
¥ STEP
3A: Ignore any background values in a dataset by creating a 
mask with 3dAutomask
mask with 3dAutomaskGValues in the
background have very low baseline values, which can lead to artificially large percent
signal change values. LetÕs remove
them altogether by creating a mask of our
dataset, where values inside the brain are assigned a value of Ò1Ó
and values outside of the brain (e.g., noise) are assigned a value of
Ò0Ó
GThis mask will be
used later when the percent signal change in each voxel is calculated. A percent change will be computed only
for voxels inside the mask
GA mask will be
created for each of Subject EDÕs time shifted, volume registered, and blurred
3D+time datasets:
foreach run (1 2 3
4 5 6 7 8 9 10)3dAutomask
-prefix mask_r{$run} \ ED_r{$run}_vr_bl+origendåOutput of 3dAutomask: A mask dataset for each 3D+time dataset:
mask_r1+orig,mask_r2+orig É mask_r10+orig