leadfieldmatrix!

[Muthuraman Muthuraman]

Hello Fieldtrippers,


I am using the DICS algorithm for the source analysis, in which i am
successfull upto the freqanalysis calculating coherence
the next step inorder to use the source analysis.

I construct the leadfield matrix the parameters are

vol   = [];
vol.r = 12 * [0.88 0.92 1.00];
vol.c = [1 1/80 1];
vol.o = [0 0 0];
cfg1            = [];
cfg1.elec       = elec;
cfg1.vol        = vol;
cfg1.resolution = 1;
grid = prepare_leadfield(cfg1,freqmtmfft);

I am constructing a volume conduction model with the elec file[standard
locations from the Sphere2 ]
which is been constructed for the 55 electrodes which i use for the source
analysis, i get these warnings
is it because the locations which i use from the standard location files.

using headmodel specified in the configuration
using electrodes specified in the configuration
selected 55 electrodes
8 dipoles inside, 0 dipoles outside brain
making tight grid
8 dipoles inside, 0 dipoles outside brain
computing leadfield
computing leadfield 1/8
Warning: electrodes do not ly on sphere surface -> using projection
>In fieldtrip-20070109\private\eeg_leadfield4 at 60
  In fieldtrip-20070109\private\compute_leadfield at 435
  In prepare_leadfield at 209

and when i go on further with the source analysis with this leadfield matrix
has

cfg.frequency=9;
cfg.method='dics';
cfg.grid=grid;
cfg.elec=elec;
cfg.vol=vol;
[source]=sourceanalysis(cfg,freqmtmfft);

%PLOTTING SOURCE


cfg.location='interactive';
cfg.funparameter='source';
cfg.maskparameter='source';
sourceplot(cfg,source);

and when i use the source plot i get the errors

updating homogenous coordinate transformation matrix
??? Error using ==> horzcat
The following error occurred converting from char to cell:
Error using ==> cell
Conversion to cell from char is not possible.

Error in ==> fieldtrip-20070109\private\parameterselection at 77
    if ~issubfield(data, param{i}) && issubfield(data, ['avg.' param{i}])

Error in ==> volumedownsample at 139
cfg.parameter = parameterselection(cfg.parameter, source);

Error in ==> sourceplot at 203
interp = volumedownsample(tmpcfg, interp);


sorry for the long mail
Thanking you

with regards
M.Muthuraman.

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