I’ve used fmriprep to preprocess my fMRI BOLD data and FSL FEAT to run a first-level analysis. To be able to run the higher-level analysis in FEAT I’ve created a reg folder with symbolic links to the functional, anatomical and template images and included the identity matrices as .mat files. Subsequently, I ran featregapply to also get this into the reg_standard folder. A similar approach has been discussed earlier: https://neurostars.org/t/performing-full-glm-analysis-with-fsl-on-the-bold-images-preprocessed-by-fmriprep-without-re-registering-the-data-to-the-mni-space/784.
However, when I compare the images before and after the application of featregapply, I notice that the image is reflected across the Z-axis (a left right swap) after the application of featregapply (Voxel: X= 28 , Y=54, Z=45 with MNI-152 coordinates -34.5, -18.5, 17.5; is similar to voxel: X= 62 , Y=54, Z=45 with MNI-152 coordinates -34.0, -18.0, 18.0 after featregapply). The MNI-coordinates do not change and the value of the voxel doesn’t change. Now I wonder if this is a problem for further analysis?
Thank you in advance for your advice!