Dear DCMers,
Currently I'm doing some analyses using the method described in Large-scale DCMs for resting-state fMRI (
https://www.mitpressjournals.org/doi/pdf/10.1162/netn_a_00015). At this stage, I'm simply trying to replicate the method (same ROI selection) using my own resting state fMRI dataset (8 min resting state).
However, I got some unexpected results - the DCM models of all subjects converged at 22nd step, and all the DCM.Ep.A matrix are almost symmetric (only tiny value differences between the upper and lower triangular matrix).
One thing to mention is that I didn't use GLM to extract the time courses, because I was not able to extract time courses of all ROIs by using the regressor of DCT between 0.0083-0.15 Hz+WM+CSF+head motion and an F contrast to test for DCT effects.
I simply used DPABI to extract time courses and implemented them according to DCM required structure. The functional connectivity of these time course is very similar to the ones shown in the Large-scale DCM paper and also the original ROI-proposing paper The Restless Brain (https://www.liebertpub.com/doi/10.1089/brain.2011.0019). I thus assumed the time courses are correct.
Did anyone come across similar problem? If so, could you please give a hand? Thank you very much!
Best,
Andrea
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