Hi Teodora,

While SPM spatially normalized volumes have lines like "SPM originator decodes to 31 43 25" in their .hdr files, this convention is outside the Analyze 7.5 specification. Unfortunately, the Analyze format doesn't specify origin and orientation information as unambiguously as the AFNI .HEAD file does.

I have a script <a href=http://brainmap.wustl.edu/donna/spm2afni.sh>spm2afni.sh</a> that uses the SPM originator tag with AFNI's 3dANALYZEtoAFNI and 3drefit to set the ORIGIN in AFNI. But you have to be careful with this. If you are aligning anatomical and functional volumes written out in the same voxel dimensions and bounding box, it will work fine; however, if you write out the anatomy in, say, cubic 1mm voxels and the functional in cubic two or three mm voxels, there will be a noticeable offset when viewing the functional volumes over the anatomical. In these cases, I've found I'm better off using 3drefit to set the functionals' ORIGIN to the anatomical's ORIGIN.

Donna