SPM12 Unwarp / Realignment Probs Across Timepoints

Summary of what happened:

Hello, all. I’ve been experiencing difficulties getting SPM12 to properly unwrap and realign participant data across timepoints as part of the SPM12 / CONN processing pipeline. For a subset of participants, the realignment procedure fails miserably, and we can’t figure out why. All participant data is centered with the origin at the AC along the AC-PC line, and all timepoints were coregistered to the baseline (but not resliced). Any thoughts on why SPM12 may be failing unwarp and realign in these circumstances? Work-arounds or solutions would be most appreciated! Thanks, Jeff

Command used (and if a helper script was used, a link to the helper script or the command generated):

No error code generated, as SPM12 doesn't recognize an error, but the mean functional image over time clearly shows non-overlap.

Version:

Matlab R2023b / SPM12 / CONN 22.a

Environment (Docker, Singularity / Apptainer, custom installation):

Data formatted according to a validatable standard? Please provide the output of the validator:

PASTE VALIDATOR OUTPUT HERE

Relevant log outputs (up to 20 lines):

PASTE LOG OUTPUT HERE

Screenshots / relevant information:

As a follow-up, the issue was resolved. The problem wasn’t with SPM code, but in the refusal of MacOS to accept the bspline.mex file permissions. Without the bspline SPM code, realignment was going to never work for greatly askew acquisition images.