[Mne_analysis] computing peak frequency in source space

[Luke Bloy]

Thanks for the quick reply Denis.

I'm interested in the peak frequency within a band not the power timecourse
of the band so source_band_induced_power isn't what I want. I also want to
stick with MNE, as opposed to DICS or another beamformer, for localization
since I will want to compare with mne/dspm power estimates.

The other complicating factor is that I'm using resting state data (~~ 5
minutes), so most of the inverse operator code in python runs into memory
problems. Otherwise I could just do apply_inverse and then work on the
returned timecourses in the stc.

once I have a time course for each source finding the peak frequency will
be pretty straight forward using numpy.fft and numpy.fft.fftfreq.

Hope this makes sense
-Luke



On Mon, Sep 30, 2013 at 12:14 PM, Denis-Alexander Engemann <
denis.engemann at gmail.com> wrote:

> Hi Luke,
>
>
> On Mon, Sep 30, 2013 at 6:02 PM, Luke Bloy <luke.bloy at gmail.com> wrote:
>
>> Hi all,
>>
>> I am interested in computing the peak frequency within a band for each
>> source.
>>
>> So my first question is does this already exists somewhere?
>>
>>
>
> This example might be of interest.
>
>
> http://martinos.org/mne/auto_examples/time_frequency/plot_source_space_time_frequency.html#example-time-frequency-plot-source-space-time-frequency-py
>
> Basically it returns source estimates per frequency band each of which can
> be visualized on e.g. a cortical surface.
>
> Another timely alternative is the DICS bearmformer recently added by Roman:
>
>
> https://github.com/mne-tools/mne-python/blob/master/examples/inverse/plot_dics_source_power.py
>
>
> https://github.com/mne-tools/mne-python/blob/master/examples/inverse/plot_dics_beamformer.py
>
> you can always use numpy.argmax and argsort functions to quickly navigate
> through peaks inside the resulting arrays.
>
>
> If not what would people suggest as a jumping off point for developing it.
>> I was thinking of following apply_inverse in inverse.py until I get the
>> final inverse operator (K in line 753) and then looping through each row
>> (source) in K to compute the time course and peak power and frequency. Any
>> other suggestions or downsides to this approach?
>>
>>
> Maybe let's first see whether what is implemented so far gives you what
> you're looking for.
>
> I hope this helps + cheers,
> Denis
>
>
>> Thanks,
>>  Luke
>>
>>
>
>
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