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