Dear list,
I've noticed a change in the one-sample t-test design matrices produced by SPM8 compared to SPM5. I seem to remember SPM5 used to (automagically?) include subject effects, with columns for each subject in the design matrix, but SPM8 doesn't do that anymore. Is there a setting change I can make to reintroduce subject effects in my design matrix?
On a related note, is there any reason not to include the global covariate (ANCOVA) in a one-sample t-test of fMRI data? I've noticed I often get more regionally specific activation with higher t-values in my results when I include the global covariate. I'm guessing this is because of subject-specific effects which I would like to remove/minimise.
Best,
Rich
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