[FieldTrip] Amplifier for EGI-data in fieldtrip???

Ingrid Nieuwenhuis inieuwenhuis at berkeley.edu
Tue Sep 4 22:00:03 CEST 2012

Hi Daria,

Also, did you try looking at your raw data (so before the ERPs are made) 
in FieldTrip and in Net Station? So open your .raw data in NetStation. 
You can just look at a random participant's data, and check if the scale 
is the same. I'm pretty sure no amplification takes place when reading 
in the data into FieldTrip, this check can confirm that. Hope this 
helps, and let us know what you find.


On 9/3/2012 1:35 PM, Robert Oostenveld wrote:
> Hi Daria,
> There might indeed be an incompatibility in the gain  value applied to 
> the data.
> If you are able to export the data using the EGI software in another 
> format (e.g. EDF), you could read them both into FieldTrip and compare 
> the timecourse aplitudes to check whether they are different. In case 
> they are, I suggest to involve EGI support. They are aware of the 
> FieldTrip reading functions and will know much more about the 
> internals of their various file formats.
> best regards
> Robert
> On 3 Sep 2012, at 17:22, Daria Laptinskaya wrote:
>> Dear Fieldtrippers,
>> I analysed EGI-data (.raw-files, NetStation 4.3.) with the fieldtrip 
>> toolbox.
>> The ERPs look perfect.
>> The 'only' problem is, that my signals look to strong.
>> It looks like if I get amplitutes (average) until 70 ┬ÁV.
>> I think it must be an intern amplifier for the signals.
>> Does anyone know this problem with EGI-data?
>> Or does anyone know, where I can see the amplifier?
>> Greetings,
>> Daria _______________________________________________
>> fieldtrip mailing list
>> fieldtrip at donders.ru.nl <mailto:fieldtrip at donders.ru.nl>
>> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip
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Ingrid Nieuwenhuis PhD
Postdoctoral Fellow
Sleep and Neuroimaging Laboratory
Department of Psychology
University of California, Berkeley
California 94720-1650
Tolman Hall, room 5305

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