acf parameters

AFNI Message Board
1

Hi all,
I just ran 3dMVM on a dataset. However, I now need to threshold the data. I want to use 3dClustSim, but now the -acf option has changed to take a, b, and c parameters.Also, when I load in the dataset, the FDR values are not showing up. Are there any suggested values for these? Is there a way to estimate them? I don’t want to fall back to the fwhm option. Also, i there a refit command I need to issue to get the FDR values to display? On the output, I saw FDR values flash by.
Thanks,
Matt

2

I load in the dataset, the FDR values are not showing up

Did the FDR q-values show up before? You can use

3drefit -addFDR -FDRmask yourMask yourFile

to add back the FDR q-values.

As for 3dClustSim, you can use

3dHWHMx -acf

on the residuals at the individual level to estimate the ACF parameters.

3

Ugh, I don’t have those, just the 1st level beta images (I didn’t do the first level analyses). If it helps, we used 3dBlur_to_FWHM setting a FWHM of 8mm. Is there any alternative approach?

Thanks.

Matt Hoptman

4

If it helps, we used 3dBlur_to_FWHM setting a FWHM of 8mm. Is there any alternative approach?

In that case, just use 3dClustSim -fwhm, which is good enough as an approximation.