Hello,
It is my first time doing a DCM analysis. We are performing an emotional task (fearful, neutral faces) DCM analysis.
Our SPM design for the DCM model has 3 columns: the fearful faces, neutral faces and the task (all faces-neutral and fearful). The fearful and neutral is the modulation (B matrix) and the task is the driving input (C matrix). For extracting the time-series we need an F-contrast ("effect of interest") to adjust the data. We cannot set up the contrast to be CON1 as the effect of interest, but if we didn't have the 3rd column (task) the contrast for calculating the effect of interest would be CON2. Can we extract the time-series from CON2 but do the DCM analysis on the first design matrix? But isn't this going to produce wrong time-series?
CON1 = [1 0 0
0 1 0]
CON2 = [1 0
0 1]
Best regards,
Georgia
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