[FieldTrip] How to obtain the frequency power spectrum of ica components?

Roey Schurr roeysc at gmail.com
Wed Aug 6 09:07:38 CEST 2014


Dear Ashly,

I'm trying to recreate the error you got, but I couldn't.
Did you specify the method? Try using
      comp.cfg.previous.method = 'mtmfft';

When I run ft_freqanalysis using the mtmfft method on the comp structure I
get from the ICA tutorial, everything seems to work fine. Did  you try
running the same function on a tutorial structure?

Best.
Roey


On Wed, Aug 6, 2014 at 8:12 AM, Ashley Greene <agreene24 at gmail.com> wrote:

> Hello,
>
> I'm somewhat new to ft, so forgive me if this is a seemingly trivial
> question.
> I ran runica on ft preprocessed MEG data, but I also want to see the
> frequency power spectrum of the components. I've tried using freqanalysis
> on the components in the following manner:
>
>
> comp.cfg.previous.tapsmofrq=4;
> comp.cfg.previous.foi=[0:2:30];
> comp.cfg.previous.t_ftimwin = 5./comp.cfg.previous.foi;
> comp.cfg.previous.toi=[-0.5:0.05:1.5];
> comp.cfg.previous.channel='all';
>
> [freqcomp] = ft_freqanalysis(comp.cfg.previous, comp)
>
>
> // but the errors I receive are as follows:
>
>
> Warning: Input arguments must be scalar.
> > In specest/private/ft_preproc_polyremoval at 57
>   In ft_specest_mtmfft at 66
>   In ft_freqanalysis at 526
> ??? For colon operator with char operands, first and last operands must be
> char.
>
> Error in ==> ft_preproc_polyremoval at 58
> for i = 0:order
>
> Error in ==> ft_specest_mtmfft at 66
>   dat = ft_preproc_polyremoval(dat, polyorder, 1, ndatsample);
>
> Error in ==> ft_freqanalysis at 526
>         [spectrum,ntaper,foi] = ft_specest_mtmfft(dat, time, 'taper',
> cfg.taper, options{:}, 'feedback', fbopt);
>
> // Is using freqanalysis on the components possible? If so, what needs to
> be modified in order to employ it? If not, is there another method to
> outputting the frequency power spectrum of ica components?
>
> Thanks,
>
> Ashley
>
>
>
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