I just starts learning AlphaSim, and have a question on the choice of a mask for smoothness estimation in 3dFWHMx.
My study is to use voxel-based GM measure to perform statistical analysis. So the mask in statistical analysis was a GM mask.
However, when I use 3dFWHMx to estimate smoothness for running 3dClustersim later on, I am confused on how to choose the right mask. Should I use the whole brain mask, or should I use the GM mask to estimate smoothness?