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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



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