[FieldTrip] missing pos in beamforming
Jason Chan
chan at med.uni-frankfurt.de
Fri Mar 16 15:17:09 CET 2012
Hi Michael,
Many thanks for your informative reply. I was able to use the reverse normalization technique and eliminated the ft_sourceinterpolate and ft_volumenormalise commands.
However, after I subtract ‘sourceA’ from ‘sourceB’ I now get the error “different grid locations in source reconstructions” when I try to do a ft_sourcegrandaverage. Any suggestions would be very welcome.
Thanks in advance.
Jason
From: fieldtrip-bounces at donders.ru.nl [mailto:fieldtrip-bounces at donders.ru.nl] On Behalf Of Michael Wibral
Sent: Mittwoch, 14. März 2012 20:29
To: Email discussion list for the FieldTrip project
Subject: Re: [FieldTrip] missing pos in beamforming
Dear Jason,
the pos indicates where the original sources were (i.e. on a regular grid with a certain spacing or self-defined). After interpolation this information does not reflect the data anymore. I would suggest to use Ingrid nieuwenhuis famous reverse normalization technique to create individual subject grids taht all match in MNI space - the script is found on the ft website. Sourceinterpoltae should really only be used for plotting IMHO.
Michael
Gesendet: Mittwoch, 14. März 2012 um 17:28 Uhr
Von: "Jason Chan" <chan at med.uni-frankfurt.de>
An: fieldtrip at donders.ru.nl
Betreff: [FieldTrip] missing pos in beamforming
Greetings,
I am adapting the beamformer tutorial to my data. When I sourceinterpolate the subtracted sourceA from sourceB data, the ‘pos’ disappears. This seems to be important for the volume normalization and Grand Average. I am running Fieldtrip version: 20110917. I have placed the code below.
Many thanks in advance.
Jason
Young_CombineFilter_sourceDiff_16_3={};
for i=1:length(Young_CombineFilter_beamform_16_3);
cfg=[];
Young_CombineFilter_sourceDiff_16_3{i} =Young_CombineFilter_beamform_16_3{i}.sourceA;
Young_CombineFilter_sourceDiff_16_3{i}.avg.pow =(Young_CombineFilter_beamform_16_3{i}.sourceA.avg.pow - Young_CombineFilter_beamform_16_3{i}.sourceB.avg.pow)./Young_CombineFilter_beamform_16_3{i}.sourceB.avg.pow;
cfg = [];
cfg.downsample = 2;
cfg.parameter = 'avg.pow';
cfg.anatomy = mri{i};
cfg.keepfilter='yes';
cfg.interpmethod='linear';
Young_CombineFilter_sourceDiffInt_16_3{i}=ft_sourceinterpolate(cfg,Young_CombineFilter_sourceDiff_16_3{i}, mri_young{i});
end;
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20120316/69848e59/attachment-0001.html>
More information about the fieldtrip
mailing list