mne and ft_sourceinterpolate
jan.schoffelen at DONDERS.RU.NL
Fri Aug 20 15:01:53 CEST 2010
What you want to achieve is as of yet not possible.
Ft_sourceinterpolate at the moment only interpolates functional
parameters which are scalars, e.g. power, or variance averaged over
time (in lcmv).
We are working at the moment to make the data representation of
different types of source reconstructed results more consistent
(beamformer versus mne etc), and first will work towards the
possibility of visualizing the functional data (including their time
courses) without the interpolation. The thing you can do now is to
define a meaningful summary statistic of the reconstructed time
course, interpolate this one on the anatomy, and click around the
anatomical coordinate of your source of interest. Subsequently you
need to reverse engineer (undo the interpolation) to find the
corresponding source position in your source structure. Then you can
use the plot command to look at the time courses.
On Aug 20, 2010, at 2:13 PM, Gregor Volberg wrote:
> Dear fieldtrippers,
> I am trying to extract source activity from timelock-data, and I
> would like to have this for a whole epoch of 1 sec / 501 sample
> points. I did an ft_sourceanalysis with method = 'mne', which worked
> fine and gave the desired source activity (see structure "source"
> below; field "avg" contains "mom" and "pow"). Next I did an
> ft_sourceinterpolate with "source" and a standard mri as input.
> Unfortunately, the resulting structure did not contain an "avg"
> field any more (see "ivol" below) - my functional data got lost
> during interpolation. Did someone have a similar problem or does
> someone know a solution?
> Many thanks in advance for any help!
> P.S.: Source interpolation works without problems with method =
> 'lcmv', but this gives the mean source activity within the desired
> time range rather than sample-wise activity. It is not a good idea
> to apply the lcmv beamformer to consecutive time bins and then
> concatenate the source activity, am I right?
> source =
> xgrid: [-66 -56 -46 -36 -26 -16 -6 4 14 24 34 44 54 64]
> ygrid: [-105 -95 -85 -75 -65 -55 -45 -35 -25 -15 -5 5 15 25 35
> 45 55 65]
> zgrid: [-46 -36 -26 -16 -6 4 14 24 34 44 54 64 74 84]
> dim: [14 18 14]
> vol: [1x1 struct]
> time: [1x501 double]
> pos: [3528x3 double]
> inside: [1x1808 double]
> outside: [1x1720 double]
> method: 'average'
> avg: [1x1 struct]
> cfg: [1x1 struct]
> ivol =
> inside: [181x217x181 logical]
> dim: [181 217 181]
> transform: [4x4 double]
> anatomy: [181x217x181 uint8]
> cfg: [1x1 struct]
> Dr. rer. nat. Gregor Volberg <gregor.volberg at psychologie.uni-regensburg.de
> > ( mailto:gregor.volberg at psychologie.uni-regensburg.de )
> University of Regensburg
> Institute for Experimental Psychology
> 93040 Regensburg, Germany
> Tel: +49 941 943 3862
> Fax: +49 941 943 3233
> The aim of this list is to facilitate the discussion between users
> of the FieldTrip toolbox, to share experiences and to discuss new
> ideas for MEG and EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html
> and http://www.ru.nl/neuroimaging/fieldtrip.
Dr. J.M. (Jan-Mathijs) Schoffelen
Donders Institute for Brain, Cognition and Behaviour,
Centre for Cognitive Neuroimaging,
Radboud University Nijmegen, The Netherlands
J.Schoffelen at donders.ru.nl
The aim of this list is to facilitate the discussion between users of the FieldTrip toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html and http://www.ru.nl/neuroimaging/fieldtrip.
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