Dear SPM
I am performing simple block design experiments (fMRI) of photic stimulation on a control group and disease group. I will aim compare the two groups eventually in an RFX analysis.
What are the difference between explicitly modelling the baseline condition (as a periodic OFF condition) and letting SPM implicitly model it e.g. the design orhogonality is different for each and I do not know how SPM interprets this? Which model should I choose or does it not really matter?
Thanks
Ahmed Toosy
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