Hi Rick,
Thanks for the corrections. How would you recommend that I proceed to blur only in the gray matter mask? One way I have tried is going into the output script and changing the Mmask parameter in 3dBlurInMask to the gray matter mask produced by afni, but I'm not sure if this the best way.
On another note, I noticed that the GM mask created by afni does not have as many voxels as I need. Is there a way to decrease the threshold to increase the amount of voxels?
Daniel