Dear Juan,<div><br></div><div>I downloaded your data to replicate the problem. I could not. It just worked. Follow these steps.</div><div><br></div><div>1. Download the latest version of EEGLAB.</div><div>2. File - Import data - Using EEGLAB functions and plugins - From Neuroscan .cnt file</div>
<div><br></div><div>I saw your photos. Apparently you failed in importing the data.</div><div><br></div><div>Makoto </div><div><br><div class="gmail_quote">2013/3/19 Juan Carlos Haro Vicente <span dir="ltr"><<a href="mailto:jharovicente@gmail.com" target="_blank">jharovicente@gmail.com</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear Makoto;<br>
<br>
I am thinking that the data provided is not correct. Trying what you<br>
said I obtain next results:<br>
<br>
<a href="http://www.flickr.com/photos/94067049@N03/8572065878/" target="_blank">http://www.flickr.com/photos/94067049@N03/8572065878/</a><br>
<br>
And, if we focus on channels one by one, we can see a different<br>
between odd and couple channels:<br>
<br>
<a href="http://www.flickr.com/photos/94067049@N03/8572065998/" target="_blank">http://www.flickr.com/photos/94067049@N03/8572065998/</a><br>
<br>
<a href="http://www.flickr.com/photos/94067049@N03/8572066088" target="_blank">http://www.flickr.com/photos/94067049@N03/8572066088</a><br>
<br>
After filtering:<br>
<br>
<a href="http://www.flickr.com/photos/94067049@N03/8572066054" target="_blank">http://www.flickr.com/photos/94067049@N03/8572066054</a><br>
<br>
<a href="http://www.flickr.com/photos/94067049@N03/8572065968" target="_blank">http://www.flickr.com/photos/94067049@N03/8572065968</a><br>
<br>
<a href="http://www.flickr.com/photos/94067049@N03/8572065936" target="_blank">http://www.flickr.com/photos/94067049@N03/8572065936</a><br>
<br>
I have asked the person who gave me the data and they said this is a<br>
valid EEG signals. Maybe, It is because the way I use for importing,<br>
those are .CNT files and I am only able to import them using "From<br>
other formats using FILE-IO toolbox" and then I obtain next warning:<br>
<br>
------------------------------------------------------------------------------------------------------------------------------------------------------------<br>
Warning CNTOPEN: month and day were mixed up 2007-15-5-13-17-37<br>
WARNING SOPEN(CNT): OVERFLOWDETECTION might not work correctly. See<br>
also EEG2HIST and read<br>
<a href="http://dx.doi.org/10.1016/S1388-2457(99)00172-8" target="_blank">http://dx.doi.org/10.1016/S1388-2457(99)00172-8</a> (A. Schlögl et al.<br>
Quality Control ... Clin. Neurophysiol. 1999, Dec; 110(12): 2165 -<br>
2170).<br>
A copy is available here, too:<br>
<a href="http://pub.ist.ac.at/~schloegl/publications/neurophys1999_2165.pdf" target="_blank">http://pub.ist.ac.at/~schloegl/publications/neurophys1999_2165.pdf</a><br>
Warning CNTOPEN: month and day were mixed up 2007-15-5-13-17-37<br>
Reading data in CNT format...<br>
Warning SREAD(CNT): could not read 2.053672e+006 samples, only 2053672<br>
samples read<br>
------------------------------------------------------------------------------------------------------------------------------------------------------------<br>
<br>
I have uploaded one of these files to dropbox in case someone wants to see it:<br>
<br>
<a href="https://www.dropbox.com/s/9an7cl7mhzv8smx/isabel_parp_correg.cnt" target="_blank">https://www.dropbox.com/s/9an7cl7mhzv8smx/isabel_parp_correg.cnt</a><br>
<br>
Regards and thanks again<br>
<br>
Juan Carlos<br>
<br>
<br>
<br>
2013/3/19 Makoto Miyakoshi <<a href="mailto:mmiyakoshi@ucsd.edu">mmiyakoshi@ucsd.edu</a>>:<br>
<div class="HOEnZb"><div class="h5">> Dear Juan,<br>
><br>
> Amplitude level of -110 dB/Hz^2 is like 100000 times smaller than my data.<br>
> Something is wrong.<br>
><br>
> Please follow these steps for diagnosis.<br>
> 0. make sure you are using the latest EEGLAB<br>
> 1. import your data straight from your raw data<br>
> 2. copy and paste these lines<br>
><br>
> figure; bar(std(EEG.data,0,2));<br>
><br>
> This is to see standard variation for all channels. In the plot, the unit is<br>
> microvolt.<br>
><br>
> figure; plot(EEG.data(1,:))'<br>
><br>
> This is to see time series of one channel. Here 1 is channel number. Change<br>
> it to other channels to see the difference. In the plot, the unit is<br>
> microvolt.<br>
><br>
> 3. apply 1 Hz (0.5 is fine) high-pass for all channels and run the above<br>
> test 2 again.<br>
><br>
> What do you see?<br>
><br>
> Mikolaj's initial guess is right: if the data were DC recorded, the data can<br>
> contain huge baseline drift (several thausands) that can completely mess up<br>
> spectopo plots.<br>
><br>
> Makoto<br>
><br>
> 2013/3/15 Juan Carlos Haro Vicente <<a href="mailto:jharovicente@gmail.com">jharovicente@gmail.com</a>><br>
>><br>
>> Dear EEGLAB list;<br>
>><br>
>> This is my first post, I am a student from Spain who is doing a thesis<br>
>> about signal processing using EEGLAB. First of all, I want to say<br>
>> thank you for all the info and help that I found here. It has been<br>
>> provided to me data from different subjects in an experiment about the<br>
>> process of different languages. Once I export this data to EEGLAB I<br>
>> have 66 channels of information which look like EEG signals. I extract<br>
>> my epochs and here, it comes the problems. When I represent the<br>
>> channel spectra and maps it shows me next picture:<br>
>><br>
>> <a href="http://www.flickr.com/photos/94067049@N03/8558863353/" target="_blank">http://www.flickr.com/photos/94067049@N03/8558863353/</a><br>
>><br>
>> Which, as I think, it is very differents from what I have to expect.<br>
>> If I see a channel, I obtain what I think is normal:<br>
>><br>
>> <a href="http://www.flickr.com/photos/94067049@N03/8559971178/" target="_blank">http://www.flickr.com/photos/94067049@N03/8559971178/</a><br>
>><br>
>> And the channel ERP scalp map shows me a signal without sense:<br>
>><br>
>> <a href="http://www.flickr.com/photos/94067049@N03/8558863377/" target="_blank">http://www.flickr.com/photos/94067049@N03/8558863377/</a><br>
>><br>
>> After seeing this, I continued with ICA analysis, once I did, I<br>
>> obtained next result for spectra maps:<br>
>><br>
>> <a href="http://www.flickr.com/photos/94067049@N03/8559971126/" target="_blank">http://www.flickr.com/photos/94067049@N03/8559971126/</a><br>
>><br>
>> Again, far away from what I expected. If I represent components ERP in an<br>
>> array:<br>
>><br>
>> <a href="http://www.flickr.com/photos/94067049@N03/8558863349/" target="_blank">http://www.flickr.com/photos/94067049@N03/8558863349/</a><br>
>><br>
>> where we can see what it looks like ERPs, but very contaminated by noise.<br>
>><br>
>> After say my situation, I would like to ask you if you have any idea<br>
>> about what it is the problem with the data. I trust your experience<br>
>> with the software and good management of these situations<br>
>><br>
>> Thank you very much<br>
>> Regards<br>
>><br>
>> Juan Carlos Haro<br>
>> _______________________________________________<br>
>> Eeglablist page: <a href="http://sccn.ucsd.edu/eeglab/eeglabmail.html" target="_blank">http://sccn.ucsd.edu/eeglab/eeglabmail.html</a><br>
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><br>
><br>
><br>
><br>
> --<br>
> Makoto Miyakoshi<br>
> JSPS Postdoctral Fellow for Research Abroad<br>
> Swartz Center for Computational Neuroscience<br>
> Institute for Neural Computation, University of California San Diego<br>
</div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br>Makoto Miyakoshi<br>JSPS Postdoctral Fellow for Research Abroad<br>Swartz Center for Computational Neuroscience<br>Institute for Neural Computation, University of California San Diego<br>
</div>