[Eeglablist] How to convert EEGlab real coordinate system to MNI coordinate system

[Arnaud Delorme]

Hi Jody,

Make sure you uncheck the checkbox “Export label only” otherwise the plugin will not export coordinates. It will export the channel labels which Loreta cannot recognize. If you uncheck the checkbox then it will export your channel coordinates in the MNI space.

Best wishes,

Arno

> On Oct 2, 2018, at 1:53 PM, Jody Zhou <jodzhou at ucdavis.edu> wrote:
> 
> Hi Arno,
> 
> Thanks for the video. I tried the plugin. However, because the GSN 129 electrode coordinate is not based on the 10-10 system or 10-20 pr 10-5 system,  the list of the electrode label doesn't match to any of the Talairach label used in LORETA.  I think the coordinate I have is real coordinate, so I also tried the "electrode coordinates maker" (in Talairach space) based on extended 10/10 system template. However it requires Nasion, Inion, left pre-auricular and right pre-auricular  fiducials' location but the GSN electrode coordinate only contains the three of the four fiducials not the Inion. 
> 
> Here is the sfp file including just Cartesian coordinate but for all the 128 electrodes and the three fiducials (Nz,Left-auricular(T9) and right-auricular(T10)). 
> https://drive.google.com/file/d/1UoHU1dVYP76Kmu-PCCpoBwvlHQr07KI8/view?usp=sharing
> 
> I've read some tutorial for alignment and co-registering. Is that what I should try? 
> 
> Best
> Jody
> 
> On Tue, Oct 2, 2018 at 10:35 AM Arnaud Delorme <arno at ucsd.edu> wrote:
> Hi Jody,
> 
> This is a relevant question. If you are using the Loreta 2.0 plugin in EEGLAB, it will convert your electrode coordinates to MNI. This plugin was made to export ICA components, but you can replace the content in the text files generated (comp1.txt etc…) by your ERD activity across channels. See this video for a tutorial.
> 
> https://www.youtube.com/watch?v=amttvN_Sb6A
> 
> Best wishes,
> 
> Arno
> 
> > On Oct 1, 2018, at 2:54 PM, Jody Zhou <jodzhou at ucdavis.edu> wrote:
> > 
> > Hi all,
> > 
> > I want to use sLORETA to conduct source localization of ERD. However, the electrode coordinate template that I use ( the old GSN 129 electrode coordinate)
> >  has a different electrode coordinate system (different origin, different spherical direction and organization) than the MNI coordinate system sLORETA uses. So I'm wondering how to convert this coordinate file  to MNI coordinate system. Thanks! 
> > 
> > Here I link the GSN 129 electrode coordinate elements including the real spherical and cartesian coordinate:  
> > 
> > https://drive.google.com/file/d/1tI6QWySUDjCC3BoYhE1Hfny2zPnEjpq7/view?usp=sharing
> > 
> > Best
> > Jody
> > 
> > 
> > Best
> > Jody
> > 
> > 
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