Confounds from fmriprep: which one would you use for GLM?

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  1. In the documentation, it is written that : we have one row per timepoint/volume.
    Is every volume compared to the first volume or to the previous volume?

In general no. In case of DVARS and FramewiseDisplacement the measure is a corresponds to a difference/variance between the corresponding timepoint and the next one (that’s why the last value is ‘n/a’)

  1. Are the 6 motion parameters in mm ?

No. Translations are in mm, but rotations are in radians.

  1. To process the GLM analysis do we use this following nifti file :
    bold_space-T1w_preproc.nii.gz ?

Only if you analyze a single subject of you do withing subjects design. For group analysis (most studies) you need the file in a common space - for example *space-MNI152NLin2009cAsym_preproc.nii.gz

Can I know why do you prefer aCompCor to tCompCor ? Is it because the mask provided is an anatomical mask so aCompCor is equivalent to CompCor ?

I don’t know what do you mean by CompCor, but I prefer aCompCor because it is more theory driven.

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