[FieldTrip] how to combining gradiometer/magnetometer sensors - neuromag(elekta) data

[mikkelcv at drcmr.dk]

You can use ft_appenddata to merge dataset with different channels; for example MEG data, EEG data, and extra channels:
%% Append all data
cfg = [];
preprocessed_data = ft_appenddata(cfg, preprocessed_data_MEG, preprocessed_data_EEG, preprocessed_data_ExG);

If they all have the same sample info FieldTrip will know to append them as different channels on the same trial.

Best regards
Mikkel


Fra: fieldtrip <fieldtrip-bounces at science.ru.nl> på vegne af bagen hasi via fieldtrip <fieldtrip at science.ru.nl>
Dato: onsdag, 27. april 2022 kl. 11.08
Til: fieldtrip at science.ru.nl <fieldtrip at science.ru.nl>
Cc: bagen hasi <hasibagenedu at gmail.com>
Emne: [FieldTrip] how to combining gradiometer/magnetometer sensors - neuromag(elekta) data
Does anyone know how to use fieldtrip to merge two separate files (mag, grad) back into one?
I did grad and mag separately and saved them separately when I was doing ICA.
But now I want to do source positioning, and I want to use all channels together for source positioning, how do I merge grad and mag back into one folder?

Can I just merge the Matlab structure of grad and mag files? Will some information be lost this way?

This is my previous code

%% magnetometers ICA
cfg=[]; cfg.channel={'MEG*1'};
data_orig=ft_selectdata(cfg,data);
save(['sub2019' subjectID{x} '_origmag.mat'],'data_orig', '-v7.3');

%% planar gradiometers ICA
cfg=[]; cfg.channel={'MEG*2','MEG*3'};
data_orig=ft_selectdata(cfg,data);
save(['sub2019' subjectID{x} '_origgrad.mat'],'data_orig', '-v7.3');

I searched a previous question, but I didn't find in it exactly how to do this, and I also searched the fieldtrip GitHub site, but I didn't find the relevant statements either.

https://mailman.science.ru.nl/pipermail/fieldtrip/2017-May/037417.html

I was wondering if you could help me with this?

Thank you for your time and I look forward to hearing from you soon!

Best regards,
Hasi Bagen
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