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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April 12, 2022 12:07PM
Hi all,

I want to do a paired t-test using 3DMEMA for a dataset where each participant was scanned twice (t1, t2). I modeled the data with 3dDeconvolve separately for each participant and each session. In the 3dMEMA example for paired t-tests it seems to me like there is only one beta-coef (B+tlrc) and one t-stat (T+tlrc) BRIK necessary for each subject and contrast:

Example 3 --- Paired type (difference of two regression coefficients or
general linear contrasts from each subject in a group). One scenario of
general linear combinations is to test linear or higher order trend at
individual level, and then take the trend information to group level.
---------------------------------
3dMEMA -prefix ex2 \
-jobs 4 \
-missing_data happyMiss+tlrc sadMiss+tlrc \
-set happy-sad \
ac ac_hap-sad_B+tlrc ac_hap-sad_T+tlrc \
ejk ejk_hap-sad_B+tlrc ejk_hap-sad_T+tlrc \
...
ss ss_hap-sad_B+tlrc ss_hap-sad_T+tlrc \

To me this looks odd becaue I have two timepoints per contrast per subject and I wonder how is this accounted for in the code. Here is an example of my data:

subject 1 subject1_time1_con1_B+tlrc subject1_time1_con1_T+tlrc
subject 1 subject1_time2_con1_B+tlrc subject1_time2_con1_T+tlrc

Can you please advise me on how to organize the data that time is accounted for?

Bests,
Philipp
Subject Author Posted

3dMEMA paired-t test

philippn April 12, 2022 12:07PM

Re: 3dMEMA paired-t test

gang April 13, 2022 11:14AM

Re: 3dMEMA paired-t test

philippn April 14, 2022 01:49PM

Re: 3dMEMA paired-t test

gang April 15, 2022 08:29AM