Hi FSL experts,
Here is my task design: Event related, with two conditions: faces and shapes. There is otherwise jittered fixation.
I am trying to model PPI for faces - shapes.
Previously, I ran:
EV1: CondA - CondB
EV2: Physio
EV3: CondA-CondB *physio (PPI of interest)
EV4: CondA+CondB
I just tried adding a 5th regressor, as recommended by Donald.
EV5: CondA+CondB* Physio (PPI)
However, I still received the same warning "Problem with processing the model: Warning: at least one EV is close to a linear combo of the others" Design matrix is rank deficient - ratio of min:max eigenvalues in SVD of matrix is 1.26154e-08)".
Any assistance on how to properly run the GLM for this PPI would be appreciated. Would it work to just remove both the EV4 and EV5?
Thank you,
M
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