Hi,

I tried it, using the default 3dclustsim values but the result does not appear to change (in the SUMA rendering) if I change the number of voxels so I was not sure that I was doing this correctly. Since you say it should be possible, I will try this again.

Btw, I was reading: [afni.nimh.nih.gov]
and there is this statement:
"Notably, real FMRI data does not actually have a Gaussian-shaped ACF, so the
estimated ACF is then fit (in 3dFWHMx) to a mixed model (Gaussian plus
mono-exponential) of the form
ACF(r) = a * exp(-r*r/(2*b*b)) + (1-a)*exp(-r/c)
where 'r' is the radius, and 'a', 'b', 'c' are the fitted parameters."

Is there a reference for this statement?

Many thanks,
Ranjan