Correct! Switching the orders of the inputs will switch the assignment of the fwd and bak fields, which will otherwise be the same in both cases. Cheers, /Eugenio

-- Juan Eugenio Iglesias http://www.jeiglesias.com

From: freesurfer-bounces@nmr.mgh.harvard.edu on behalf of Codrin Mironiuc codrinmironiuc@yahoo.ro Reply-To: Freesurfer support list freesurfer@nmr.mgh.harvard.edu Date: Thursday, March 16, 2023 at 10:12 AM To: "freesurfer@nmr.mgh.harvard.edu" freesurfer@nmr.mgh.harvard.edu Subject: [Freesurfer] Question on EasyReg forward field

External Email - Use Caution Hi,

I am trying to shift the statistical maps that I obtained from a second-level fMRI analysis (meaning across multiple sessions for one subject).

My plan is to use EasyReg to align the functional data to the structural data. Based on the resulting field then I intend to use it to shift the statistical maps using mri_easywarp.

I know that for EasyReg, it doesn't matter the order in that I provide the arguments, e.g.

Order 1: mri_easyreg --ref <structural_image> --flo <functional_image>

Would produce the same result as

Order 2: mri_easyreg --ref <functional_image> --flo <structural_image>

Nevertheless, I believe that depending on whether I choose 'Order 1' or 'Order 2', I would need a different field to allign the statistical maps, would this be correct? I think that if I choose Order 1, then the backward field is needed, whereas if I choose Order 2, I would need the forward, field, right? Or would it be the forward field for both Orders that is needed in order to allign the statistical maps from the second level (across runs for a single subject)?

Many thanks! Codrin