problem partially solved

Andrew Smart at NYU.EDU
Thu Apr 19 21:43:45 CEST 2007

Hi Jan,
Thanks for the answer, everything works now ok.

I did follow this FIXME in freqstatistics

% FIXME in the hase of coherence, the code above does not work since "label" is then incorrect.
% marbas reported the following
%   als ik freqstatistics gebruik om coherence data te analyseren met
%   cfg.parameter = coherence, dan wordt het powspctrm vervangen door
%   het cohspctrm. Het laatste heeft echter 1 kanaal minder (dwz als
%   er 1 referentiekanaal in zit), waardoor de informatie uit data.label
%   niet meer klopt, en freqstatistics crasht. Data.label zou, in geval
%   van cfg.parameter = coherence, moeten worden vervangen door
%   data.labelcmb(:,2), dan werkt het wel.

And I changed prepare_timefreq_data

output.label = input.label:


output.label  = input.labelcmb;

Otherwise fieldtrip crashes because the structure of the coherence data does not have a label field, but a labelcmb with the coherence between channels and the ref channel.

Is there a way to get fieldtrip to accomodate coherence structures?


----- Original Message -----
From: Jan Mathijs Schoffelen <jan.schoffelen at FCDONDERS.RU.NL>
Date: Thursday, April 19, 2007 3:22 pm
Subject: Re: [FIELDTRIP] problem partially solved

> Dear Andy,
> Please allow me to point you to the fact that fieldtrip has no
> restriction on the type of data you want to cohere. The rather mundane
> reason why the tutorial documentation on coherence is about
> cortico-muscular stuff, is related to the fact that the interpretation
> of cortico-muscular coherence is far more straightforward than the
> interpretation of coherence between EEG/MEG-channels, or between
> virtual electrodes/dipoles. However, the statistical routines don't
> care whether the coherence spectra you pass to them are between
> similar channels, or between dipole locations in the brain.
> Yours,
> Jan-Mathijs
> ----- Original Message -----
> From: Andrew Smart < at NYU.EDU>
> Date: Thursday, April 19, 2007 5:43 pm
> Subject: [FIELDTRIP] problem partially solved
> > Hi,
> > I found why I was getting the error
> > embarrassingly I had {i} instead of {:}!
> >
> > My general question remains about the possibility of doing
> > statistical group
> > analysis on coherence between BESA dipoles, or in source space in
> > general.
> > It seems most of the coherence analyses are set up to do coherence
> > betweenchannels and an external reference such as EMG.
> >
> > Thanks and sorry for all the messages!
> >
> > andy

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