Dear expert

i have read about the importance of implementing noise smoothness information within cluster-based correction methods (particularly when using 3DClustSim). I have been running a VBM analysis and am trying to calculate the appropriate cluster size under which my findings remain valid using an initial cluster defining p<0.001 and alpha of 0.05.

My questions are:
- is the acf smoothness calculation needed for VBM studies too (as it usually refer to fMRI findings)
- could anyone provide me with help on how to implement this?

what i currently did is using the following command:
./3dClustSim -mask gm_multiple_r_mask.nii.gz -fwhm 8 -pthr .1 .05 .02 .01 0.005 0.001 -prefix 3dclustsim_gm_multiple_r_mask

as a mask i used my DARTEL template that was constructed for the present adolescent sample in order to reduce the correction to gray matter volume.

Thanks a ton on any input/help!
Bernadette