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The longer you make the highpass setting the *less* it will remove - so if you want to get more aggressive, you need to *reduce* the setting. On 15 Oct 2011, at 19:00, Varina Wolf wrote: > Hello FSL Experts, > > I am using FEAT to pre-process (with ICA denoising) prior to MELODIC on a resting state individual analysis prior to group analysis.. > > I have one patient who had particularly noisy data, and in an effort to filter out more of the noise, I did several runs with incrementally higher values of the High Pass Filter (s) - 100, 250, 500, 750, 1000, 3000, 6750, 9000. > > The outcome showed improving noise removal with fewer and less noisy components after ICA in FEAT. But no difference past 6750 s. > > - I note an output document stating the cap on the filter is 1000, yet the results improved past this value. Why? > - How does the Temporal Filtering High Pass effect this? > - After FEAT, do I need to put the same time cut off for Melodic? > - I suppose I need to use the same High Pass Filter for all of my data to have uniform group analysis later? > > Best regards, > Varina > --------------------------------------------------------------------------- Stephen M. Smith, Professor of Biomedical Engineering Associate Director, 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 ---------------------------------------------------------------------------