Dear SPM:
Tried searching through the archives but couldn't find quite the answer I
was looking for so here goes...
fmri study
2 similar study types.
2 conditions per study (rest and active)
1 subject reaction time score per study
Did random effects analysis- to produce 2 images per study for each
subject, used proportional scaling and hi pass filter.
Entered into multi-study conditions and covariates design.
# studys- 2
# subjects in study 1 = 14
# conditions in study 1 = 2
entered the scans
# subjects in study 2 = 12
# conditions in study 2 = 2
entered the scans
covariates = 1
I took each subject's score (26 scores), mean corrected the lot and then
entered it as
-p1 p1 -p2 p2 ... (where pn is the subject's study specific and mean
corrected score). I didn't divide by 2.
No specific fits.
No scaling
No global norm.
Contrasts
The main effect of each study
study 1 = -1 1 0 0 0
study 2 = 0 0 -1 1 0
The interaction with the covariate
0 0 0 0 +1
0 0 0 0 -1
Is this correct- I really just want to see the effect of the covariate.
Thanks,
Darren
Darren R. Gitelman, M.D.
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