I am trying to get a correlation matrix of voxel time-series, that sit along the gray matter (GM) of a common template. So, I need an preprocessed EPI image and GM template (based on t1), that both lie on the same template.
My target template is MNI152_2mm_brain. Using fmriprep (1.1.2), I could get EPI images realigned to this target template (figure, right). And, it also produced a beautiful GM probabilistic map realigned to the MNI152NLin2009cAsym template (figure, left).
The question is: How to bring the GM map to my target template? Is there already some fmriprep options to specify MNI152_2mm_brain as the target space for anatomical preprocessing? Or, shall I go for nipype functions for the volume resampling?
I would really recommend you to use the MNI152NLin2009cAsym template that comes with fMRIPrep. However, if for whatever reason that is not possible, you can:
Use the GM map that comes with the MNI152 2mm linear directly. I’d say the registration error can be dismissed, as this map will be a lot smoother than that of MNI152NLin2009cAsym.
Resample the GM map into your target MNI152 2mm linear. See Normalization of fmri data without changing voxel size for a similar problem). For improved alignment, you may run a nonlinear registration between MNI152NLin2009cAsym and MNI152 2mm linear.
Please check my answer to your other thread. Just to clarify: “mismatched sampling grid” != “misaligned”. Samples may be in different locations in space, but information may be indeed aligned (in register).
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