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

History of AFNI updates  

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November 25, 2002 10:43AM
Dear AFNI experts,

I have 2 groups of subjects: each subject performed a test with 4 conditions. First I created 4 regressors (using waver), and then I used 3dDeconvolve, giving for each subject a brick with least squares estimates of b0 (constant term), of b1 (linear trend), and of h1, h2, h3, h4 (my four regressors). All results look fine.
Next, I want to use 3dANOVA2 to compare activation between the two groups and I wonder what images to use for input. I would prefer to use the % signal change of (h2-h1, h3-h1 and h4-h1), corrected for each subject's own baseline. I have tried (waver amplitude)*(h2-h1) / b0, but the numbers I get are much smaller than I would expect (that is, << 1%). Any ideas what I am doing wrong?

A second question I have is whether it would also be sensible to use (for example) only the h2/b0 images as input image for 3dANOVA2, instead of pairwise differences between hx/b0 and hy/b0?

Thanks a lot,
Serge.
Subject Author Posted

% signal change after 3dDeconvolve results

serge November 25, 2002 10:43AM

Re: % signal change after 3dDeconvolve results

bob cox November 25, 2002 03:01PM

Re: % signal change after 3dDeconvolve results

Jim Eliassen November 25, 2002 03:35PM