Hi, Rujing-

I do remember, indeed-- nice to be able to have met the AFNI user behind the MB posts!

Rick mentioned that there was a script that he had written for running 3dClustSim on surfaces for the multiple comparisons correction, called "slow_surf_clustsim.py" in large part because it is... kinda slow.

Note that at present this program does not run 3dClustSim with the new "ACF mixed model" smoothing estimates; it runs it just with a Gaussian approximation. If you have followed some of the clustering news in the past couple years, in volumetric data it was shown that Gaussian estimates of smoothness were not very good. *However*, the blurring/smoothing performed on the surface is done *differently* than that of the volume-- instead of just blurring with a Gaussian over the data, the surface smoothing blurs *to* a given Gaussian smoothness.

This is an example of surface smoothing from the afni_proc.py surface-proc script example created by the AFNI_data6/FT_analysis/s03* command in the AFNI Bootcamp data:

SurfSmooth -spec $surface_dir/std.60.FT_${hemi}.spec         \
                       -surf_A smoothwm                                  \
                       -input pb03.$subj.$hemi.r$run.surf.niml.dset      \
                       -met HEAT_07                                      \
                       -target_fwhm 6.0                                  \
                       -blurmaster pb03.$subj.$hemi.r$run.surf.niml.dset \
                       -detrend_master                                   \
                       -output pb04.$subj.$hemi.r$run.blur.niml.dset     \
                       | tee surf.smooth.params.1D

Note the use of "-target_fwhm ..." Also note that this processing+estimation is done hemisphere-by-hemisphere.

Also note that we haven't looked at this for a cluster-control FPR test like the Eklund et al. folks set up (where they called resting state data "null" data and assumed every cluster found would be a false one). This is a fairly different scenario to the volumetric one in a couple subtle (and not-so-subtle) ways, so it might be pretty different.

--pt