afni.nimh.nih.gov

If you REALLY want to do prewhitening without regression against any task or regressors, 3dREMLfit cannot do that. However, it CAN do a very minimal regression without a task matrix from 3dDeconvolve. The minimal matrix is the single column of all 1s -- if you don't supply a '-matrix' option, this is what it will use. The result will be that the estimated mean is regressed from each voxel, and '-Rwherr' output will be the prewhitened results from that.