Unless it's been changed, I don't think it's a single interpolation.  Also I don't think it's a spline interpolation.

Peace,

Matt.

From: Diederick Stoffers <[log in to unmask]>
Reply-To: FSL - FMRIB's Software Library <[log in to unmask]>
Date: Monday, October 7, 2013 12:23 PM
To: <[log in to unmask]>
Subject: Re: [FSL] Apply rs-fMRI motion correction and fieldmap-based unwarping in a single interpolation

Feat will do this for you.

Cheers,

Diederick

On 7 Oct 2013, at 18:54, Torsten Rohlfing <[log in to unmask]> wrote:

Hi All:

In our rs-fMRI data, we would like to correct both B0 field-induced distortion (using FUGUE) and motion (using mcflirt?), but in a single (!) interpolation operation.

Is it possible to perform a single reslice using the concatenation of fieldmap-based unwarping and rigid motion transformation? Would we do this using flirt, can fugue do it, or would we need to do some more involved transformation computations?

Hope this makes sense. Thanks!

Torsten