AFNI Message Board

Dear AFNI users-

We are very pleased to announce that the new AFNI Message Board framework is up! Please join us at:

https://discuss.afni.nimh.nih.gov

Existing user accounts have been migrated, so returning users can login by requesting a password reset. New users can create accounts, as well, through a standard account creation process. Please note that these setup emails might initially go to spam folders (esp. for NIH users!), so please check those locations in the beginning.

The current Message Board discussion threads have been migrated to the new framework. The current Message Board will remain visible, but read-only, for a little while.

Sincerely, AFNI HQ

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gang
October 11, 2016 11:26AM
Christine,

> My independent variable is Time. It has 4 levels and it is a repeated measure. I also have 3 nuisance
> behavioral measures that I would like to covary out of the analysis of the effect of Time. These three
> measures also change with the passage of Time (e.g., memory accuracy, memory confidence, and
> response time).

With within-subject covariates, 3dLME is definitely the solution for you.

> I would like to look at the effect of Time on brain activity with concomitant changes in those 3 nuisance
> measures covaried out.

Be careful about centering if each of those covariates has different means across the 4 levels of Time: [afni.nimh.nih.gov]

> Would it also improve the model to include inter-subject differences in the three covariates? That is,
> should I include a component in the model that codes for differences in memory accuracy, memory
> confidence, and response time across participants?

I don't see any rationale for doing so if you've already incorporated those 3 covariates in the LME model.

Gang
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Subject Author Posted

3dLME vs 3dMVM

Christine Smith October 10, 2016 02:29PM

Re: 3dLME vs 3dMVM

gang October 11, 2016 11:26AM