[FieldTrip] Source localization

[jan-mathijs schoffelen]

Hi Casper,

Looks like a lowlevel error to me.
The function complains about the dim not having the number of elements it expects (should be 3). Thus it looks as if the input to the plotting function (thus the output to ft_sourceinterpolate) is unexpected.

Best,
Jan-Mathijs


On Jan 18, 2013, at 3:53 PM, Casper van Heck wrote:

> Dear Fieldtrippers,
> 
> I've asked this question earlier, but either it got lost due to technical reasons, or the people who actually understand what's happening here were on vacation, so here it is again:
> 
> I've been trying to do a source analysis on a dataset with two conditions, mostly following the tutorials and examples from the Fieldtrip site, and come upon a problem; it won't plot. While the source analysis is not an essential component of the analysis of this dataset (it's more along the lines of "let's see if I can do this"), and I don't expect any result other than something like "there might be a source in the left hemisphere", I'd still would like to found out why it's not working.
> 
> Essentially, I create a standard headmodel cause I don't have individual MRI's from the "Subject1.mri"-example, using ft_volumesegment, ft_prepare_headmodel and ft_prepare_sourcemodel, and try to get Fieldtrip to find sources based on individual EEG-datasets using ft_freqanalysis (with cfg.method = 'mtmfft') and ft_sourceanalysis. 
> After that, I use ft_sourcegrandaverage to produce, well, a grand average source, and feed this via ft_sourceinterpolate to ft_sourceplot.
> 
> Now, ft_sourceplot has three plotting possibilities: slice, ortho, and surface. Initially I tried to get the ortho-option to work, but this gave the following error:
> Attempted to access dim(3); index out of bounds because numel(dim)=2.
> Error in ==> cornerpoints at 11
> Error in ==> ft_plot_slice at 157
> 
> So, I tried the surf-option, which gave me this:
> Undefined function or variable "val".
> Error in ==> ft_sourceplot at 1174
> 
> And finally, I tried the slice-option, which gave one of two errors (which seems to be based on how many slices I requested):
> Out of memory
> Which is pretty damn impressive since I've got 8GB of RAM and a pagefile topping of at 40GB
> Or, the mildly disconcerting:
> Matlab has encountered an internal error and has to close
> Which seems to have been caused by a so-called "Segmentation violation"
> 
> Can anyone offer any insight in these errors? I think I'm doing something wrong pretty early on, but have no idea what it is.
> 
> Sincerely,
> 
> Casper van Heck
> 
> 
> On Fri, Dec 21, 2012 at 1:43 PM, Casper van Heck <caspervanheck at gmail.com> wrote:
> Dear Fieldtrippers,
> 
> I've been trying to do a source analysis on a dataset with two conditions, mostly following the tutorials and examples from the Fieldtrip site, and come upon a problem; it won't plot. While the source analysis is not an essential component of the analysis of this dataset (it's more along the lines of "let's see if I can do this"), and I don't expect any result other than something like "there might be a source in the left hemisphere", I'd still would like to found out why it's not working.
> 
> Essentially, I create a standard headmodel cause I don't have individual MRI's from the "Subject1.mri"-example, using ft_volumesegment, ft_prepare_headmodel and ft_prepare_sourcemodel, and try to get Fieldtrip to find sources based on individual EEG-datasets using ft_freqanalysis (with cfg.method = 'mtmfft') and ft_sourceanalysis. 
> After that, I use ft_sourcegrandaverage to produce, well, a grand average source, and feed this via ft_sourceinterpolate to ft_sourceplot.
> 
> Now, ft_sourceplot has three plotting possibilities: slice, ortho, and surface. Initially I tried to get the ortho-option to work, but this gave the following error:
> Attempted to access dim(3); index out of bounds because numel(dim)=2.
> Error in ==> cornerpoints at 11
> Error in ==> ft_plot_slice at 157
> 
> So, I tried the surf-option, which gave me this:
> Undefined function or variable "val".
> Error in ==> ft_sourceplot at 1174
> 
> And finally, I tried the slice-option, which gave one of two errors (which seems to be based on how many slices I requested):
> Out of memory
> Which is pretty damn impressive since I've got 8GB of RAM and a pagefile topping of at 40GB
> Or, the mildly disconcerting:
> Matlab has encountered an internal error and has to close
> Which seems to have been caused by a so-called "Segmentation violation"
> 
> Can anyone offer any insight in these errors? I think I'm doing something wrong pretty early on, but have no idea what it is.
> 
> Sincerely,
> 
> Casper van Heck
> 
> _______________________________________________
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> fieldtrip at donders.ru.nl
> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip

Jan-Mathijs Schoffelen, MD PhD 

Donders Institute for Brain, Cognition and Behaviour, 
Centre for Cognitive Neuroimaging,
Radboud University Nijmegen, The Netherlands

Max Planck Institute for Psycholinguistics,
Nijmegen, The Netherlands

J.Schoffelen at donders.ru.nl
Telephone: +31-24-3614793

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