Hello,
I read about 3dClustSim in this forum. I am now using it for my SPM analyses. I still have 2 questions:
1. I know that SPM.xVol.FWHM gives the residual smoothness in voxels, and this is what I need to enter as smoothness in 3dClustSim (as milimeters). However, should I take the SPM.xVol.FWHM information from the SPM.mat of a participant (1st-level analysis) or from the SPM.mat of a 2nd-level analysis ? or it doesn't matter it should be the exact same residual smoothness ? Because I noticed slight changes of residual smoothness from different 2nd-level contrasts.
2. I do not quite understand the -BALL option in 3dClustSim. Are people using it ? What is the rationale for using that option ?
Thank you very much,
Josiane Bourque
University of Montreal
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