[FieldTrip] Source localization using DICS for EEG data from combined MEG/EEG recordings

[Johanna Zumer]

Dear Marcel,
I might have seen a similar error before when the number of channels in
'elec' do not match the number of channels in 'freq'.   Could that be the
cause?

Also, does it matter that you are setting cfg.grad=elec, rather than
cfg.elec=elec?

To debug, it might be best to first call leadfield=ft_prepare_leadfield()
to ensure that is computed correctly, and then set that output to
cfg.grid.leadfield=leadfield, in your call to ft_sourceanalysis.

cheers,
Johanna

2012/6/26 Marcel Heers <marcel.heers at googlemail.com>

> Dear all,
>
> I am trying to perform source localization in the frequency domain
> from EEG data using DICS. The data were recorded combined with MEG
> (Neuromag data format).  The volume conductor is a 3 shell realistic
> head model created with bemcp.
> When running DICS with the following settings
>
> cfg                   = [];
> cfg.method       = 'dics';
> cfg.grad            = elec;
> cfg.frequency    = 14;
> cfg.vol              = vol_eeg;
> cfg.dics.projectnoise = 'yes';
> cfg.dics.lambda       = 5;
> source = ft_sourceanalysis(cfg, freq);
>
>
> I am am getting the following error message:
>
> ??? Error using ==> svd
> Input to SVD must not contain NaN or Inf.
>
> Error in ==> beamformer_dics>pinv at 568
>   [U,S,V] = svd(A,0);
>
> Error in ==> beamformer_dics at 314
>         filt = pinv(lf' * invCf * lf) * lf' * invCf;              %
> Gross eqn. 3, use
>         PINV/SVD to cover rank deficient leadfield
>
> Error in ==> ft_sourceanalysis at 584
>       dip(i) = beamformer_dics(grid, sens, vol, [],
> squeeze(Cf(i,:,:)), optarg{:});
>
>
> and I am not sure what might be the cause.
>
> Maybe anyone can help me! Thank you in advance!
>
> Marcel
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