[FieldTrip] Defining cfg.neighbourdist at source level

[smoratti at psi.ucm.es]

Dear Robert,

To do clustering on a 3D source surface I always had to "trick" field trip and squeezed the 3D source surface data into a ERF structure treating the 3D surface points as sensors. Then by triangulation I found the neighbors. However, if there is a more elegant method implemented in ft_sourcestatistc, I would be very interested to know how to do it. Where can I find some hints on that?

Best,

Stephan

________________________________________________________
Stephan Moratti, PhD

see also: http://web.me.com/smoratti/

Universidad Complutense de Madrid
Facultad de Psicología
Departamento de Psicología Básica I
Campus de Somosaguas
28223 Pozuelo de Alarcón (Madrid)
Spain

and

Center for Biomedical Technology
Laboratory for Cognitive and Computational Neuroscience
Parque Científico y Tecnológico de la Universidad Politecnica de Madrid
Campus Montegancedo
28223 Pozuelo de Alarcón (Madrid)
Spain


email: smoratti at psi.ucm.es
Tel.:    +34 679219982

El 31/01/2012, a las 15:37, Robert Oostenveld escribió:

> Dear Ulrich
> 
> If your source locations are defined on a regular 3D grid that can be represented as volume, then the neighbours are trivial to find and you do not have to specify a structure for the neighbours. 
> 
> If you have done source reconstruction on a 3D folded cortical sheet that is defined by a triangulated surface, then it is also possible to cluster along the surface. I don't know the details for the cortical sheet clustering from the top of my head, if you are interested please let me know and I'll look them up.  
> 
> best
> Robert
> 
> 
> 
> 
> On 30 Jan 2012, at 16:58, Pomper, Ulrich wrote:
> 
>> Dear Jörn,
>> Thanks for you reply. I did mean source-level, so like you said, I am trying to define the neighbouring voxels for each voxel.
>> As far as I understand, leaving cfg.neighbours blank means that the clustering is done over the time and frequency dimensions only, not over space. 
>> The FT help reads: 
>> %If you specify an empty neighbourhood structure, clustering will only be done in frequency and time (if available) and not over neighbouring channels.
>> 
>> Has anybody done clustering in source space using all three dimensions and could explain how this works?
>> Cheers, 
>> Ulrich
>> 
> 
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