On 21 Oct 2015, at 19:56, Riley North <[log in to unmask]> wrote:

Dear FIX users,
I have a related question. I am trying to create fALFF/ALFF metrics from FIX processed data, and therefore I need to avoid high-pass filtering.

I can't quite see the logic - the lowest frequency artefactual trends could easily confound FALFF measurements (which are hard enough to interpret already!)

I see that when running the motion parameter correction in FIX there is an option [-h] to apply "highpass filtering of motion confounds." Is this just the application of a high-pass filter to the data, OR is the filter applied to the motion confounds in a way that does not directly affect the remaining frequencies in the data?

More like the latter - it's for the case where data has already been high-pass filtered, and in order to correctly regress the motion confounds out of the data, these confounds first need to have the same highpass filtering applied.

Cheers

Thanks in Advance,
-Riley

---------------------------------------------------------------------------
Stephen M. Smith, Professor of Biomedical Engineering
Head of Analysis, Oxford University FMRIB Centre

FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve

---------------------------------------------------------------------------

Stop the cultural destruction of Tibet