[Mne_analysis] mne-python lcmv

[Martin Luessi]

Hi Jon,

I can see distinct boundaries as well, so they do not seem to be caused 
by your setup. I'm not sure what is causing this and we have to 
investigate why the boundaries occur. The beamformer does correctly 
localize the activity, have a look at the screenshot below (frame 61 in 
the nifit file, corresponding to 100ms).

As noted in the documentation, our LCMV code has not been heavily 
tested, so the boundaries might indeed be caused by an error in the code.

Note that the dSPM volume inverse (link below) does not show these 
boundaries and also correctly localizes the bilateral activity. If it is 
an option for you, you could use this method instead of LCMV.

Best,

Martin


http://martinos.org/mne/auto_examples/inverse/plot_compute_mne_inverse_volume.html#example-inverse-plot-compute-mne-inverse-volume-py



On 03/10/13 19:39, Jon Houck wrote:
> Hi all,
>
> I'm consistently seeing distinct boundaries within my lcmv estimates,
> and am wondering what might be wrong with my setup.  The images below
> are axial and coronal slices from the nifti file produced by the lcmv
> example with the sample data
> (http://martinos.org/mne/auto_examples/inverse/plot_lcmv_beamformer_volume.html).
>    These boundaries are consistent throughout the timecourse (on
> Dropbox, see link below).
>
> I've re-run the volume data tutorial and the lcmv inverse example, but
> still see this effect. The slice and timecourse figures that I get from
> the example script look identical to the output on the website, so it
> may be something specific to the final step.  I'm using 0.6 of
> mne-python (downloaded this week) with EPD, and a recent nightly build
> of MNE.  Any ideas on what might be happening?
>
> Inline image 3Inline image 4
>
> https://www.dropbox.com/s/nkvw9mn4hio5yp7/lcmv_inverse.nii.gz
>
> Thanks,
>
> Jon
>
>
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-- 
Martin Luessi, Ph.D.

Research Fellow

Department of Radiology
Athinoula A. Martinos Center for Biomedical Imaging
Massachusetts General Hospital
Harvard Medical School
149 13th Street
Charlestown, MA 02129

Fax: +1 617 726-7422
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