[Eeglablist] reference during import of EMG data acquired with Biosemi

[Guillaume Chanel]

Hello Sebastian,

as you record EMG in a biopolar setup I would say that you do not need 
to do any referencing: just substract the two electrodes signals. With 
comparison to EEG this would be similar to a reference with regard to a 
single channel and thus should also remove the noise.

Good processing,

Guillaume

Le 19.09.2011 16:57, seba a écrit :
> Dear eeglab specialists,
>
> I hope you can help me on this one:
>
> I have recorded facial electromyography (EMG) with a Biosemi system, and
> want to analyze it in EEGLAB/matlab.
> I am not sure about the question of the reference during importing.
>
> I know that when first importing EEG data into EEGLAB, which was
> recorded reference-free with with a Biosemi system (www.biosemi.com
> <http://www.biosemi.com>), one should indicate whatever channel as a
> reference, in order to improve the signal-to-noise ratio.
>
> However, it is unclear to me what I should do when importing into EEGLAB
> EMG data recorded with the same system.
> Should I indicate one electrode as a reference? And after having done
> so, should I rereference the data? to what?
> Or is the EMG signal so strong that one can afford to keep some noise in
> the data and therefore does not need to indicate a reference during
> importing?
> Would this also be true if I am interested in tiny EMG differences
> between conditions, as usual in facial mimicry paradigms?
>
> Thank you very much for your help.
>
> Best,
> Sebastian
>
>
>
> /----------------------------------------------------------------------/
> /Sebastian Korb, Ph.D./
> /Swiss Center for Affective Sciences/
> /University of Geneva, Switzerland/
> /Tel.: +41223799812/
> /Email: Sebastian.Korb at unige.ch <mailto:Sebastian.Korb at unige.ch>/
> /Webpage: /http://www.affective-sciences.org/user/34
>
>
>
>
>
>
>
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