[Eeglablist] uninterpretable component

[Stefan Debener]

Dear Iren,

It is difficult to evaluate the quality of a single IC without further 
information. How do the other ICs look like? Do you find many dipolar 
ICs, and reasonable artefact ICs? If not I would suspect that the 
overall quality of the decomposition is rather poor. Consider HP 
filtering and pruning your data first (see EEGLAB tutorial).
Also, are you sure you have the correct electrodes location file? It 
seems you have recorded against the left mastoid. The plot suggest one 
left lateral HEOG and one right inferior VEOG channel. We prefer not 
using bioloar recordings anymore, recording all your data against a 
common reference is usually easier (to collect and later process) and 
reveals basically the same amount of information. The evaluation of 
topographies is also complicated by a mixture of unipolar and bipolar 
channels, so this could explain some prominent features of the map you 
are showing.

Best,
Stefan


Am 3/22/11 3:03 PM, schrieb Barkaszi Irén:
> Dear all,
>
> I got an uninterpretable component in my analysis.This component's 
> scalp map is verydiffuse and the source dipole is outside the brain. I 
> would like to quantify the component's quality with a single 
> equivalent current dipole but it would entail the elimination of the 
> component, though its ERP contributes strongly to the data ERP. Do you 
> think it is correct to throw it out?
> Please find enclosed a figure about this component.
>
> Thank you in advance,
> Iren
>
>
>
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-- 
Prof. Dr. Stefan Debener
Neuropsychology	Lab
Department of Psychology
University of Oldenburg
D-26111 Oldenburg
Germany

Office: A7 0-038
Phone: +49-441-798-4271
Fax:   +49-441-798-5522
Email: stefan.debener at uni-oldenburg.de

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