Hi SPMers,
While this is not an SPM-specific post, I reckon some of you much be using structural equation modelling (SEM) for your fMRI data. I am new at SEM and I need some help on the following issues:
1. What RMSEA, GFI, and/or AGFI thresholds have you been using for your SEMs? What range of values of these measures is indicative of a good fit for a typical fMRI model?
2. Has anyone used sparsely sampled fMRI data (as in, long break of around 10 s between successive fMRI images) for SEM or DCM? What special considerations are there?
3. How do you compare the same model across two groups, e.g., patients and controls, where each group has a number of participants?
4. How do you compare the same model across two conditions of the same run, e.g., a visual task and an auditory task?
I would really appreciate any help I can get.
Thank you very much in advance,
Kwaku.
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