I am a novice of running DCM in SPM. I am doing the DCM ERP.
Here are my 3 questions:
1. In the box of "specification of effects" for between trial effects, can I input [0 -2]? What is it different from input [0 -1]?
The intrinsic (baseline) connection strength (coupling (A) in the results) will be evaluated using the response corresponding to the "0", right?
What if I have 3 responses and specify the between trial effects as [1 0 -1] to test the linear effect, what will be used to evaluate the intrinsic connection? the average of these 3 responses?
2. The coupling (B) in the results represent the posterior means and their probability of gain in all connections for modulation effects (fitting the difference between the responses in experimental condition and in baseline condition), right? Are the posterior means for the gain modulations always positive numbers? If so, where I can find the direction of modulation effects? Does it imply that the connection strength increases if the between trial effects are specified as [0 1] and decreases if specified as [0 -1]?
3. How can I batch DCM analysis for multiple participants/models in SPM? Where I can find it and what procedures I should follow?
They do puzzle me a lot. Any clarification or suggestion is welcomed. Thank you so much for answering my questions.
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