Turning off high pass filtering in nipype.algorithms.modelgen.SpecifyModel

This seems like a very simple question, but somehow I can’t find the answer! Can someone tell me how to turn off high pass filtering when setting up a model in Nipype (via SpecifyModel, to be inputted into nipype.workflows.fmri.fsl.estimate)?

We have exceptionally long events we’re modeling (120sec) so I’d rather just turn high pass filtering off, and use some longer DCT functions. I’ve been setting high_pass_filter_cutoff in SpecifyModel to 0, but I’m worried this might be causing additional problems. Is that worry justified? And if so, is there a way to simply turn high pass filtering off?


Hi @jordan_theriault ,

Did you finally solve this? I am in the same situation as you, so I am curious about how to do this.

I thought of two options, though, if not possible to turn it off through SpecifyModel. I would like to know if my rationale is OK or if someone has a better idea:

  • The quickest way would be to set the parameter high_pass_filter_cutoff to a very large value (not 0), so that it’ll be effectively keeping all the frequencies.

  • I guess you are using this SpecifyModel interface to pass it later to a Level1Design node. This will then produce a fsf file, where the value of the high pass filtering would be located (among other things). Then, I think a little function could be written after this node, such as it modifies this fsf file to turn off the high-pass filtering. In particular, It would be to set the line “set fmri(temphp_yn) 1” to “fmri(temphp_yn) 0”, I think.

Hi @jrasero!

Yeah, I’ve just been setting high_pass_filter_cutoff to 0 as I said in the original post and it seems to be working fine! If you find a problem though I’d be interested in knowing it!


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