Bad Channel Detection in CTF MEG Data Analysis

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1

Hi everyone,

I am currently working on analyzing my CTF MEG dataset and have encountered a challenge regarding bad channel detection. Specifically, I have noticed that when using Max Filter for analysis. However, it appears that my CTF data does not include the necessary “cross_talk file” and “calibration_file.” I would greatly appreciate any guidance or advice on how to address this issue and successfully perform bad channel detection and Max Filter(SSS) with my CTF MEG data. The code snippet I’m using is as follows:

auto_noisy_chs, auto_flat_chs, auto_scores = mne.preprocessing.find_bad_channels_maxwell(
    data1_check, 
    cross_talk=crosstalk_file, 
    calibration=calibration_file,
    return_scores=True, 
    verbose=True)

Best regards,

Cole

2

Hello,

I might be mistaken, but I don’t think CTF provides neither. Those are Neuromag/MEGIN files (and if I’m right, for gradiometers only). Thus, you should leave both arguments set to the default, None.

Mathieu

3 Likes
3

Thanks for your replying!
As a supplement, it is needed to specify coord_frame=“meg”

The full codes as follow

mne.preprocessing.find_bad_channels_maxwell(
raw_check, 
cross_talk=None, 
calibration=None,
return_scores=True,
coord_frame="meg", # mne has a method to transfer CTF's meg to head coord
verbose=True)

Cole

1 Like