Dear Daiming,
If you look at the attention dataset example in the SPM manual, the approach taken is to have a driving input of "task", which includes all trials, in addition to separate modulatory inputs which would correspond to your positive and negative stimuli. Would this be suitable for your design?
Best,
Peter.
-----Original Message-----
From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] On Behalf Of D. Xiu
Sent: 02 September 2014 18:41
To: [log in to unmask]
Subject: [SPM] total effect for seperated stimuli in DCM
Dear SPMers:
When I utilized the DCM to detect the emotional effect on connectivities, I specified the models with the positive stimuli and negative stimuli on the connectivities respectively. In the result matrix, the DCM give me two matrix with the parameters of modulatory effects of negative and positive stimuli separately. Now I'd like to get the total effect of emotion (positive and negative) on one connectivity. How could I get it? THX
best wishes,
Daiming
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