<div dir="ltr">Hi Ricarda,<div>Some suggestions:<br><div>1. Did you include your EXG electrodes in the re-referenced channels? Perhaps you could remove these?</div><div><br></div><div>2.Review and exclude bad channels before re-referencing? I used the Biosemi Viewer before analyzing the data in Fieldtrip.</div></div><div><br></div><div>3. Re-reference to a single channel, like CZ(A1).</div><div><br></div><div>I haven't worked with bdfs in a while, I had the same problems you're describing initially with my data. Here are a few solutions I remember offhand. I was able to resolve them without converting them to .cnt. </div><div><br></div><div>Best,</div><div><br></div><div>Raquel</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Sep 23, 2014 at 11:11 AM, Ricarda Braukmann <span dir="ltr"><<a href="mailto:r.braukmann@donders.ru.nl" target="_blank">r.braukmann@donders.ru.nl</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>Hi Rachel,<br></div><div><br></div>Yes, I was wondering about the re-referencing because I indeed read that this was the necessary first step for Biosemi data.<br>What would one usually re-reference the data to?<br><br>I
tried re-referencing to all electrodes (since no mastoid etc. has been
collected) but this did not solve the issue for the .bdf file.<br><br>It
works for the converted .edf file in which the data looks much better
from the start but I am not sure whether everything is going correctly. <br>
The data is quite noisy and also when trying to apply a high-pass filter
later Matlab gives an error of unstable poles. I am not sure whether
this is due to the actual properties of my data or whether it is still
related to the way I read it in, so any suggestions are very
welcome!<br><br>Thanks a lot!<br>Best,<br>Ricarda<div class="gmail_extra"><br><div class="gmail_quote"><br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div><div class="gmail_extra"><div class="gmail_quote"><span class="">On Tue, Sep 23, 2014 at 4:33 PM, Raquel Bibi <span dir="ltr"><<a href="mailto:bibi.raquel@gmail.com" target="_blank">bibi.raquel@gmail.com</a>></span> wrote:<br></span><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><span class=""><div dir="ltr">Hi Ricarda,<div>The Biosemi system uses CMS & DRL during acquisition as the common mode for the ground electrode. Are you re-referencing your EEG signals, before viewing them in ft_databrowser?</div><div><br></div><div>Best,</div><div><br></div><div>Raquel</div></div></span><div class="gmail_extra"><br><div class="gmail_quote"><span class=""><div><div>On Mon, Sep 22, 2014 at 10:43 AM, Ricarda Braukmann <span dir="ltr"><<a href="mailto:r.braukmann@donders.ru.nl" target="_blank">r.braukmann@donders.ru.nl</a>></span> wrote:<br></div></div></span><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div><div dir="ltr"><span class="">
<p class="MsoNormal">Hi everyone,</p><p class="MsoNormal"><br></p>
<p class="MsoNormal">I have a question regarding reading in Biosemi .bdf
files.</p>
<p class="MsoNormal"><br></p></span><p class="MsoNormal">I followed the example on the ft website to read in a .bdf
file, and - although it does not give an error- , the data looks very odd. In
the ft_databrowser for example the vertical scale is [ -178000<span> </span>178000 ] which seems very werid to me.</p><span class="">
<p class="MsoNormal"><br></p><p class="MsoNormal">I <span> </span>tried
re-referencing the data, like in the example, using channel 'EXG5', but this did
not help. </p>
<p class="MsoNormal"><br></p><p class="MsoNormal">Is there anyone who has experience with reading in biosemi files
who could give me some advice? <span><br></span></p><p class="MsoNormal"><span></span>It would
also be great if someone could explain to me what these EXG channels are
exactly.</p>
<p class="MsoNormal"><br></p></span><p class="MsoNormal">I have for now turned to converting the .bdf file to .edf
file (using the converter from <a href="http://www.biosemi.com/download/ToolsForRuntimeEngine861/Converter86.zip" target="_blank">www.biosemi.com/download/</a>). Then the data looks normal, but it created some other issues with my
markers and I would rather not use the converted files. <br></p><span class=""><p class="MsoNormal">More than anything, I am
very curious what is going on with the original file, so any help is much
appreciated!</p>
<p class="MsoNormal"><br></p><p class="MsoNormal">Thanks in advance! </p>
<p class="MsoNormal">Ricarda </p>
<br clear="all"><br>-- <br></span><div dir="ltr"><span></span><span><br>Ricard</span><span>a Braukmann, </span>MSc<span class=""><br>
PhD student<br><br> <br>Radboud University Medical Centre & Baby Research Center <br><br>Donders Institute for Brain, Cognition and Behaviour, <br>Centre for Neuroscience & Centre for Cognition<br><br>Room B.01.22<br>
Phone: +31 (0) 24 36 12652<br>Email: <a href="mailto:r.braukmann@donders.ru.nl" target="_blank">r.braukmann@donders.ru.nl</a>
</span></div>
</div>
<br></div></div><span class=""><span>_______________________________________________<br>
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<br>_______________________________________________<br>
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<a href="http://mailman.science.ru.nl/mailman/listinfo/fieldtrip" target="_blank">http://mailman.science.ru.nl/mailman/listinfo/fieldtrip</a><br></span></blockquote></div><br><br clear="all"><br></div></div></div></blockquote></div><span class=""><br>-- <br><div dir="ltr"><span></span><span><br>Ricard</span><span>a Braukmann, </span>MSc<br>
PhD student<br><br> <br>Radboud University Medical Centre & Baby Research Center <br><br>Donders Institute for Brain, Cognition and Behaviour, <br>Centre for Neuroscience & Centre for Cognition<br><br>Room B.01.22<br>
Phone: +31 (0) 24 36 12652<br>Email: <a href="mailto:r.braukmann@donders.ru.nl" target="_blank">r.braukmann@donders.ru.nl</a>
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