Hi Gang,

Sorry, I was able to figure out the issue just now. Thank you again for your help.

In your previous message, you had suggested that I include the VBM in the between subject line in the model with the assumption that the VBM values do not vary within subject. I just want to clarify whether it would be appropriate it include the VBM values in the bsVars line or the Wsvars line.

The VBM covariate is a nifti image from SPM that has GM volumes per voxel. Each participant has only one VBM nifti file (one time point). The values at each voxel for each participant do vary (because there are different GM values at each voxel). The values also differ by groups (patients show less GM volumes vs. controls). My goal is to control for the GM volumes for my fMRI analysis as there are differences in GM between the groups that could potentially be causing the fMRI results.

Thank you again.