[Eeglablist] re-reference without losing the reference channel

[arno delorme]

Dear Soyoung,

you should use the option, 'method', 'withref' when you are computing  
average reference. This way the reference channel is included in the  
average referencing process and you wlll also be able to re-reference  
to that channel later on if you want from the GUI. If you do not  
include the reference, then some information is lost and you will not  
be able to retrieve the old reference.

There is no rule for average referencing. You may include or not the  
reference as far as I know (although if it is a mastoid for instance  
M1, and you recorded M2, then you should include it so your average  
reference montage is symmetrical).

Best,

Arno

On 2 juin 08, at 10:21, Soyoung Kwon wrote:

> Dear all,
>
> How can I re-reference to one site electrode without losing the  
> reference electrode channel?
>
> 1. EEG are originally recorded in Pz reference with Forehead grounded.
>
> 2. Then, we changed the reference as average reference in eeglab
> %% EEG = pop_reref( EEG, [], 'refstate',-19);  % Pz: 19 ch
>
> Now I want to change the current average reference back to original  
> reference or other one site electrode. So, I tried this..
>
> %% EEG = pop_reref( EEG, 19, 'refstate', 'averef', 'keepref', 'on');  
> % average -->19 chan reference.
>
> But this above statement miss one electrode information.
>
> Any ideas with using pop_reref function without losing the reference  
> channel?
>
> Thanks in advance.
>
> -- 
> Research Assistant,
> Dep, of Neurology, Korea University Medical Center, Korea University  
> College of Medicine
> 126-1, 5-Ga, Anam-Dong, Sungbuk-Gu, Seoul 136-705, Korea
>
> Tel 82-2-920-5984
> _______________________________________________
> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
> To unsubscribe, send an empty email to eeglablist-unsubscribe at sccn.ucsd.edu
> For digest mode, send an email with the subject "set digest mime" to eeglablist-request at sccn.ucsd.edu