[FieldTrip] Antw: plv and sourceanalysis

[sibylle]

Dear Gregor,

I think that is exactly what I was looking for!
Thanks a lot for your fast reply, this is really helpful :)
Actually, I already ran ft_sourceanalysis (using DICS) to identify  
regions of interest.
I will have a look at the LCMV beamformer postings you've recommended.

Best wishes,

Sibylle


On 7 Apr 2011, at 14:10, Gregor Volberg wrote:

> Dear Sybille,
>
> the plv option is now within ft_connectivityanalysis. I was  
> successful with the code given below (ft_freqanalysis changed a bit  
> in newer versions of fieldtrip so there might be some small  
> corrections necessary). As much as I know, a plv analysis on source  
> activity is not implemented as one of fieldtrip's high-level  
> functions, but could be done by hand. One possibility is to use  
> source analysis to identify regions of interest, which can then be  
> used as "virtual electrodes" for ft_freqanalysis and  
> ft_connectivityanalysis, just as the real electrodes in sensor space  
> data. In order for that to work, you need to reconstruct single  
> trial source activity at your ROIs. How this is done depends on the  
> method you use for source analysis. There are some recent postings  
> where a method is described for an LCMV beamformer.
> Hope this helps,
> Gregor
>
>
> cfg_tfr                    = [];
> cfg_tfr.output             = 'fourier';
> cfg_tfr.channel            = 'all';
> cfg_tfr.method             = 'mtmconvol'
> cfg_tfr.taper              = 'hanning'
> cfg_tfr.toi                = -0.6:0.02:1
> cfg_tfr.foi                = [8 9 10 11 12];
> cfg_tfr.t_ftimwin          = 7./cfg_tfr.foi;
> cfg_tfr.channelcmb         = {'EEG', 'EEG'}
> freq_output = ft_freqanalysis(cfg_tfr,data);
>
> cfg_con = [];
> cfg_con.method = 'plv';
> plv = ft_connectivityanalysis(cfg_con, freq_output);
>
>
>
>
>
>
> -- 
> Dr. rer. nat. Gregor Volberg <gregor.volberg at psychologie.uni-regensburg.de 
> > ( mailto:gregor.volberg at psychologie.uni-regensburg.de )
> University of Regensburg
> Institute for Experimental Psychology
> 93040 Regensburg, Germany
> Tel: +49 941 943 3862
> Fax: +49 941 943 3233
> http://www.psychologie.uni-regensburg.de/Greenlee/team/volberg/volberg.html
>
>
> >>> sibylle <s.mohr at psy.gla.ac.uk> 4/7/2011 12:55 PM >>>
> Dear Fieldtrippers,
>
> I have a couple of question and I hope someone can help me:
> How is it possible to compute plv (for freq data)?
> As far as I can remember there used to be an option within
> ft_sourcedescriptives, which seems to have disappeared.
> How can one use plv to determine connectivity in source space?
>
> Thanks a lot & best wishes,
>
> Sibylle
>
>
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