[Eeglablist] Re: ERSP & ITC and DIPFIT

[Dénes Szucs]

In my experience ERSP effects are very well localized.
Is it theoretically correct to use a given frequency bin for ERSP or 
ITC for source localization in dpfit?

Thanks a lot!


> Dear Young,
> 
> >    Question 1: DIPFIT uses function dipplot() provided by eeglab itself to plot dipoles in a 3D view. And dipplot() has draw a Ellipsoid coordinates to approximate the Talariach coordinates. The question is which Talariach axis is each ellipsoid axis corresponds to.
> 
> The elipsoid in Dipfit corresponds to the coregistration of the MNI
> brain with standard EEG markers. For more details on the coregistration
> see end of section A3.5 in
> http://www.sccn.ucsd.edu/eeglab/dipfittut/dipfit.html
> 
> >    Question 2: How can I get a dipole Talariach Coordinates in eeglab?
> 
> You have to retreive the MNI coordinates of the dipoles from dipplot
> (editing of code is required to return these coordinates). Then you have
> to convert these coordinates to Tailairach (for instance use the
> function http://eeg.sourceforge.net/mridoc/mri_toolbox/mni2tal_matrix.html).
> 
> >    Question 3: Further on question 1. What is the transformation between the four-sphere head model (eeglab default settings) and the MNI coordinates?
> 
> This is performed within Dipfit (line 549). In the future, we will allow
> users to perform EEG/MRI coregistration and use homogenous matrix
> transformation in dipplot (this is already possible if you use the
> 'coreg' option of dipplot; for beta use only).
> 
> Arno
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Denes Szucs
Lecturer in Neuroscience and Education
University of Cambridge, UK
Shaftesbury Road, Cambridge, CB2 2BX, UK
Tel: +44-(0)1223 369631
Fax: +44-(0)1223 324421