DICS with external channel

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1

Hello

Do anybody out there have experience with using the DICS beamformer in MNE to find sources coherent with an external signals? E.g. using EMG to finding cortico-muscular coherence as done in the original DICS paper by Gross et al. 2001.

So far it seems that the DICS beamformer in MNE only take the cross-spectra from MEG sensors, but not able to specify CSD with a non-MEG channel. It seems that in order to calculate the CSD between MEG sensors and external reference I first have to label the external channels as an MEG channel, as mne-time_frequency.csd/csd_epochs will only calculate the CSD matrix between MEG channels. This does however not solve my next problem: that I only need the external reference-MEG CSD for the source localization. Anybody who have a workaround or solution?

Best regards
Mikkel

Mikkel C. Vinding | Ph.D. | Post doc
NatMEG - The National Research Facility for Magnetoencephalography
Department of Clinical Neuroscience | Karolinska Institutet
171 77 Stockholm | Nobels v?g 9, office D313
Phone: +46 8 524 833 33
Email: mikkel.<mailto:mikkel at vinding@ki.se>vinding at ki.se <mailto:mikkel.vinding at ki.se> | ki.se<http://ki.se/ki/jsp/polopoly.jsp;jsessionid=aMdk8ad4iRL6OYOdFn?l=en&d=130>

2

hi,

you may want to give a try to :

https://martinos.org/mne/stable/auto_examples/decoding/plot_decoding_spoc_CMC.html

then I would source localize with a dipole fit the pattern of the decoder.

Alex

3

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Hi Alex

Thank you for the answer. When I run the SPoC decoder the output is the predicted value for the reference signal. I cannot find the weights of the classifier on the sensors in any of the variables it creates:

            # Make pipeline
            clf = make_pipeline(SPoC(n_components=2, log=True, reg='oas'), Ridge())
            # Define a two fold cross-validation
            cv = KFold(n_splits=2, shuffle=False)
            # Run cross validaton
            y_preds = cross_val_predict(clf, X, y, cv=cv)

Where or how do I find the pattern of the decoder?

Best regards
Mikkel

Mikkel C. Vinding | Ph.D. | Post doc
NatMEG - The National Research Facility for Magnetoencephalography
Department of Clinical Neuroscience | Karolinska Institutet
171 77 Stockholm | Nobels v?g 9, office D313
Phone: +46 8 524 833 33
Email:?mikkel.vinding at ki.se | ki.se

4

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Dear Mikkel,

As detailed in the documentation, the weights are stored in the `filters_`
attribute.

Attributes

5

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Dear All
  I was wondering if there is a Matlab/Python version of openMEEG code,
lying around somewhere?
  It does not have to a be very well written one, just that it works.
  OpenMEEG is written in tight C++ and I would like to find out about the
various details of it, and it is just a lot of it.
best regards parham

6

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hi,

you should use the openmeeg list:

https://lists.gforge.inria.fr/mailman/listinfo/openmeeg-info

Alex