[Mne_analysis] Conflict of preprocessing recommendations: ICA and high-pass

[Stefan Appelhoff]

Dear MNE users,

I have a problem, that I would like to briefly state in three parts:

*
*

*Situation:*

- I am currently working on EEG data (64 channels, 500Hz sampling
frequency).

- I want to clean the data for blink and horizontal eye movement artifacts.

- For this purpose, I would like to use ICA first for a single subject,
to identify "templates", and then apply these templates to all subjects
using the "corrmap" approach.


*Problem:*

The conflict I encounter is when it comes to preprocessing my data:

- For ICA, a high-pass filter of 1Hz is recommended (see here
<https://martinos.org/mne/stable/generated/mne.preprocessing.ICA.html>)

- For EEG data in general, high-pass filters with a cutoff > 0.1Hz have
been shown to be problematic (see here
<https://martinos.org/mne/dev/auto_tutorials/plot_background_filtering.html#tut-filtering-hp-problems>)


*Question:*

Let's assume the following:

- Given my raw data, I create two pre-processed versions: One version
high-pass (hp) filtered at 1Hz and the other version hp filtered at 0.1Hz

- I calculate the ICA on the 1Hz hp data to obtain mixing and unmixing
matrices.

- /What are the caveats to be considered when I then apply the mixing
and unmixing matrices obtained from the 1Hz hp data to the 0.1Hz hp data? /


Help, and especially pointers to literature or examples are appreciated.

I am also open to alternative approaches to addressing my situation.


Best regards,

Stefan

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