[FieldTrip] Problem with Beamformer demo

[Schoffelen, J.M. (Jan Mathijs)]

Hi Zoltan,


Have you checked the values of the numbers in the functional data prior to calling ft_sourceinterpolate? This would give an indication of whether it is an interpolation issue or not.
I suspect that latter, because it seems that the interpolation is pulling ‘activity values’ into areas in the volume for which no functional estimate was provided.
This could happen if the specification of the ‘inside’ field in the source variable, prior to interpolation, behaves unpredictably.
Whether or not this is specific to the Matlab version used, I don’t know. Also, it is unclear what version of fieldtrip you are using.

What I can see in your script, though, is that the sourcePost_nocon you use to generate the first ‘correct’ 2 figures is loaded from disk, whereas the other source structure (with the ‘incorrect’ interpolation) is not.

Best wishes,
Jan-Mathijs


On 25 Feb 2020, at 13:46, Zoltan Juhasz <z65.juhasz at gmail.com<mailto:z65.juhasz at gmail.com>> wrote:

I have recently run into a problem while executing the Beamformer Fieldtrip demo at http://www.fieldtriptoolbox.org/tutorial/beamformer/

I am using the sample data set and the source code from this page but the picture I get for the section "Source Analysis: Contrast activity to another interval" is rather strange. I include here the 3 outputs, first two are correct, third one is the problematic one. Also included is the source. Matlab version used: R2019a. Could someone check whether it is a script error or perhaps a change in Matlab that generates the odd result?

links to figures and source:
https://drive.google.com/drive/folders/1XPZd5l3og1WAEt8dK6Bx7a9W8xgSzCMF?usp=sharing

Thanks,
Zoltan
University of Pannonia, Hungary
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