Hi Alfonso, 

The dof after denoising are between about 9 and 13. Would you consider that too low? Notably, it is not the case that the runs with the fewest dof are also the runs with strange histograms. If I do not filter the 24 realignment regressors, then the dof jump up to about 30, and the peaked histograms appear more normal. However, structured noise also reappears in the after-denoising carpet plot. I should also note that the dof are similar in the SPM preprocessing version. Looking forward to your input

Thank you,
Walter