Dear SPM experts
I have a study including two groups of subjects (patients and controls) who participated in fMRI paradigm including all together 6 conditions in a 2x3 design (observing left or right hand performing three different tasks: a,b,c). Outside the scanner, each participant rated the experienced valence for each condition. I have already done the 1st-level analysis and have the subject-wise contrasts for each of the conditions.
Now, I am also interested in to studying the main effects of group, and group*condition interactions, but at the moment my main and foremost interest is to study the effect of valence on brain responses 1) in general, and 2) in subject groups separately.
My questions is, can I use the flexible factorial design to study these effects?
For the aforementioned interests the designs I have planned would be
1) 2(GROUP:patient,control) x 2(HAND:left,right) x 3(CONDITION:a,b,c) and using valence as a covariate.
2) seperately for both groups: 2(HAND:left,right) x 3(CONDITION:a,b,c) and using valence as a covariate.
Are these designs ok? If they are, can I just use t-contrasts 1 and -1 to study the effects of valence?
Any help is greatly appreciated! Thank you in advance.
Best regards
Jaakko
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