ACF blur estimates REML

AFNI Message Board
1

Hello!

Are the AFNI ACF blur estimates supposed to be using stats.s####_REML file as the final dataset? (and if not, do you know how to change @ss_review_basic to pull the stats file rather than the REML file?)

I’ve noticed a discrepancy between the ACF blur estimate values I recorded earlier and what I am getting now. (I double-checked that I am using the same version of AFNI.) I am wondering if it is because now it’s listing the REML file as the final dataset? The differences are pretty minor but could potentially add up to influence the average ACF value…

e.g. previous: 0.431531 5.62745 12.6793

now: 0.437133 5.48647 12.5898

Thank you so much!

Best,
Leah

2

Leah,

Are the AFNI ACF blur estimates supposed to be using stats.s####_REML file as the final dataset?

Conceptually ACF/smoothness estimates should reflect the spatial relatedness in pure “noise” because you’re supposed to control “false positives” assuming there is no signal in the data under the traditional statistical framework. So, it may make more sense to use the model residuals at the subject or population level to estimate the ACF parameters.