Hi Nancy,fsl_regfilt is actually designed to regress out only parts of a design matrix - you specify the columns that you want regressed with the '-f' argument.Because you will want to regress out all columns of the design matrix generated by fsl_motion_outliers, you should pass to the -f argument a list containing the numbers of all columns in the output of fsl_motion_outliers.For example, if fsl_motion_outliers outputs a file containing 6 columns, you should call:fsl_regfilt -i input.nii -o output.nii -d motion_outliers.txt -f 1,2,3,4,5,6Cheers,PaulOn 6 May 2016 at 16:59, Nancy Li <[log in to unmask]> wrote:Hi Paul,When I excute the command"fsl_regfilt -i (input file.nii) -o (output file) -d (file produced by fsl_motion_outliers) .the result is like this:"vector::_M_range_check" .What it means and what is the correct command. Looking forward to your experienced help! Thank you so so much!BestNancy