3dFWHMx on residuals that have been censored

AFNI Message Board
1

Hi,

I am attempting to get the ACF parameters on a dataset that contains a good deal of censored points (lots of 0s in the residuals). Does this affect the estimation of the ACF parameters?

Thank you

2

Yes, you should not include all-zero time points.
Consider the way afni_proc.py does this, though
the example does not include -acf…

AFNI_data6/FT_analysis/s15.proc.FT.uber

  • rick
3

Great that’s a simple fix!

Thank you, Rick

4

Just to follow up, it turns out that the new values were only very slightly different (so much so that the values truncated to the hundredths place are exactly the same) even though we censored ~ 600 points out of ~ 2700.

Does this make sense?

5

Looking closely, the zero volumes do not actually affect
the FWHM estimates, except in that they may affect
the detrend operation. So that seems reasonable.

Thanks for mentioning it.

  • rick
6

Great, thank you for looking into it!