Dear FSL experts, I have two ROIs in MNI space, one is the seed mask and the other is the target. I can get the matrix from MNI to DTI space by using the registration tool in FDT. Is this matrix from nonlinear or linear registration? All I can see is 12 DOF between MNI and DTI, does that mean it only do the affine transformation? If I wanna give the nonlinear registration between MNI and DTI, so can the registation tool do that and what should I do? Thanks. Ran