error with sourceanalysis

Robert Oostenveld r.oostenveld at FCDONDERS.RU.NL
Mon Dec 15 11:36:54 CET 2008

My first suspicion is that there there is a problem with the
coordinate system, e.g. that you express one geometrical object (the
mri) in mm and the other geometrical object (the volume conduction
model, the eelctrode positions or the source positions) in cm.

Please use the headmodelplot function to check that the electrodes,
volume conduction model and sources are appropriately aligned to each
other. Plotting those together with the MRI is difficult, but you can
look at the positions as numbers and check that those are epressed in

best regards

On 13 Dec 2008, at 0:56, Massih Hamidi wrote:

> I am running the "localizing oscillatory sources using beamformer
> techniques" tutorial on my EEG data (imported from EEGlab) using the
> mnc t1
> template MRI (as described in the "Create BEM headmodel for EEG"
> tutorial).
> However, I get an error when running sourceinterpolate (?? Attempted
> to
> access sel(1); index out of bounds because numel(sel)=0.)
> When I plotted the output of sourceanalysis (without the anatomical
> mri), I
> get a strange pattern (attached).
> I then tried to run prepare_leadfield with cfg.mri (create the
> dipole grid
> based on segmented mri) and I was able to successfully run
> sourceanalysis
> and sourceitnerpolate, but the map of power estimates look nothing
> like what
> is shown in the tutorial (also attached).
> Plotting the data and time-frequency analysis results seem fine, so
> I don't
> think it's an import or freqanalysis problem.  Any ideas on what's
> wrong?
> Thanks.

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