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Hi Andy, Could we have some more details please to help diagnose this? 1. To confirm, you only have these two regions, or you have others too? 2. You said all stimuli drove both fusiform gyri. Did you also have inputs to the DCM distinguishing neutral from fearful faces? 3. When you do an SPM contrast of all faces, collapsed over neutral and fearful (using the same design matrix as you used to extract ROIs), do you see blobs in the same position as you extracted your ROI? How did you define your ROIs? 4. Perhaps most importantly, what's your baseline in your GLM? Is it a regressor specifically to be used as a baseline, or do you just have an implicit unmodelled baseline, e.g. ITI periods? Best, Peter. From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] On Behalf Of André Schmidt Sent: 24 July 2014 11:14 To: [log in to unmask] Subject: [SPM] negative driving inputs Dear DCM experts, I entered all possible stimuli (neutral and fearful faces) as driving inputs into the fusiform gyri (bilateral) - these C values were both negative. Does this reflect that the driving input inhibit FG activity? Is this plausible? Thanks a lot for your help. Best regards, Andy