[Eeglablist] dipole localization at ERP

[Arnaud Delorme]

Dear Francesco,

first I would be careful about applying ICA outside of EEGLAB. Most commercial software packages preprocess the data using PCA (so you do not have to review all the components) with often dramatic effects on ICA component quality. PCA should not be used before ICA unless it is absolutely necessary.

Second in the code provided on the wiki, you might want to average the ERP scalp topography over a time range rather than picking a single sample point (in this case 100 ms) before performing source localization.

I hope this helps,

Arno

On 18 Feb 2013, at 00:24, Francesco Sigona wrote:

> Hello guys,
> 
> I recently started using eeglab with which I would like to carry out a dipole fitting on ERPs data (N100).
> I usually use BrainVision Analyzer to work with ERPs, but this software cannot do the dipole localization.
> 
> I cleansed the signals with ICA (on BrainVision analyzer), I ran an average of the different epoques and I imported the data (65 sensors, 70time points) in eeglab. Then I followed the tutorial about dipfit (http://sccn.ucsd.edu/wiki/A08:_DIPFIT#Using_DIPFIT_to_fit_EEG_or_ERP_scalp_maps) but I have not got encouraging results.
> For this reason I ask you some indication of the method to be followed, if it is necessary or not perform dipfit of ICA (but which components and how should be selected?) or can I use dipfit_erpeeg.
> I really hope in a help.
> Thanks in advance.
> 
> -- 
> Francesco Sigona
> CRIL - Università del Salento
> via Pappacoda, 12
> 73100, Lecce - Italy
> web: http://www.cril.unisalento.it
> tel.: +39 0832 332097
> fax.: +39 0832 252570
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