Hi,
The unconfound program takes input data Y and confound matrix X and outputs the adjusted data Ya where:
Ya=(I-Xpinv(X))Y
If you only want to subtract one 4D file from another, on a voxelwise basis, then fslmaths should be used:
fslmaths <input> -sub <filename> <output>
Hope this helps
Matthew
> Dear Steve,
>
> We would like to subtract unique prespecified timeseries from a 4D dataset (filtered func data) in a voxelwise manner. We have used the “unconfound” program to do this, but its exact operations are still somewhat unclear to us.
>
> Does unconfound indeed calculate unique timeseries for each voxel for subtraction from the 4D dataset? If so, does unconfound use model fitting (based on the specified confound.mat matrix file), parameter estimation per voxel, multiplication of the model with the parameter estimate, followed by voxelwise subtraction of the calculated timeseries? Or does it remove a single standard timeseries from all voxels within the specified 4D dataset?
>
>
> Kind regards,
>
> Jasper Looijestijn
>
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