Hi everyone,

I am having some problems with Bayesian model selection for DCM in SPM8.  I have been using the random and fixed effects analysis, but the results have been  unusual.  Each model selected for the random effects analysis appears to have a very low log evidence in the fixed effects results, so much so that the model is not even reflected in the graphical representation.  A possible problem is that some models may have been estimated in SPM5 and some in SPM8, though all models have been specified in SPM8.  Could this affect the BMS result?  Is there a way to check to see which models were estimated in SPM8 versus 5?  I have tested the results out using different groups of models to see if the same pattern arises, particularly by grouping those that were definitely estimated in one version of SPM, and because it does, it seems as if there may be an additional technical issue.  Does anyone have any suggestions on how I could approach this problem?

Thanks for your help.
Sunali