Hi Rick,

Do you mind if I ask a few more basic questions?
1. How many regressors do you find reasonable to include? I notice that I'm running 3dTProject with a few dozen regressors, and I'm concerned this might affect the quality of the projected data. Will more regressors have a negative impact on the data's quality, or is there absolutely no relationship?
2. Is 3dTProject doing a regression analysis and keeping the residuals?
3. Are the data standardized or simply demeaned? You mentioned that demeaning occurs at the voxel-level, is it particularly advantageous to demean the data?
4. How are passband regressors generated? Are these cosine regressors? And can I generate them outside 3dTProject with an afni program (this is just for understanding, I'll use those automatically created by 3dTProject)?

Thank you very much!
Sam