Kevin,<br><br>I'm not familiar with ft_prepare_leadfield, but in the past when I had similar electrode-related error messages I was able to resolve it by first running<br><br>elec = ft_read_sens(filename, ...)<br><br>and then adding elec to the data structure. I believe the file I used for ft_read_sens was a layout file I exported from EEGLAB.<br>
<br>Best,<br>Steve Politzer-Ahles<br><br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Message: 3<br>
Date: Tue, 04 Oct 2011 14:51:29 +0200<br>
From: Kevin Lam <<a href="mailto:K.Lam@donders.ru.nl">K.Lam@donders.ru.nl</a>><br>
To: <a href="mailto:fieldtrip@donders.ru.nl">fieldtrip@donders.ru.nl</a><br>
Subject: [FieldTrip] ft_prepare_leadfield: no electrodes or<br>
gradiometers specified<br>
Message-ID: <<a href="mailto:4E8B0151.4060109@donders.ru.nl">4E8B0151.4060109@donders.ru.nl</a>><br>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed<br>
<br>
Hi all,<br>
<br>
I recorded EEG using BrainVision Recorder and have analyzed the data<br>
(ERP and TFR). Now, I would like to determine the source of the TFR<br>
effects. (I've been following, more or less, this procedure:<br>
<a href="http://fieldtrip.fcdonders.nl/tutorial/beamformer" target="_blank">http://fieldtrip.fcdonders.nl/tutorial/beamformer</a>)<br>
<br>
I'm having trouble executing ft_prepare_leadfield. Here's what I've done<br>
in the preceding steps, per participant:<br>
- ft_redefinetrial to specify the time of interest for each of the two<br>
conditions<br>
- ft_freqanalysis to calculate CSD matrix per the freq of interest for<br>
each condition<br>
- ft_volumesegment using 'spm' for coordsys<br>
- ft_prepare_headmodel using 'singlesphere' for method<br>
<br>
Now, when I attempt ft_prepare_leadfield, I get an error saying 'no<br>
electrodes or gradiometers specified'. I understand what the function<br>
needs, but I don't have the input file it's asking for. It's not the<br>
.lay file - I gave this a try.<br>
<br>
Please advise. Thanks in advance!<br>
<br>
Regards,<br>
Kevin<br>
<br>
<br>
------------------------------<br>
<br>
Message: 4<br>
Date: Tue, 4 Oct 2011 15:05:10 +0200<br>
From: Davide Rivolta <<a href="mailto:drivolta81@gmail.com">drivolta81@gmail.com</a>><br>
To: Email discussion list for the FieldTrip project<br>
<<a href="mailto:fieldtrip@donders.ru.nl">fieldtrip@donders.ru.nl</a>><br>
Subject: [FieldTrip] power line filter<br>
Message-ID:<br>
<CAMkcSw7oubKNktYkJz8_V3ObcP=<a href="mailto:zbEruxRn3YLA2yBkCRhgFRg@mail.gmail.com">zbEruxRn3YLA2yBkCRhgFRg@mail.gmail.com</a>><br>
Content-Type: text/plain; charset="iso-8859-1"<br>
<br>
Dear all,<br>
<br>
I am trying to get rid of the power line noise. I use the dftfilter as<br>
indicated on the website.<br>
<br>
This works very well for most of the subjects. However, for some of them, I<br>
still get the noise.<br>
<br>
My trials have a different lenght: between 500 ms until 3 seconds.<br>
<br>
This is the script I used.<br>
<br>
<br>
filterfreqs = [49:1:51 99:1:101 149:1:151];<br>
<br>
cfg.dftfilter = 'yes';<br>
cfg.dftfreq = filterfreqs;<br>
cfg.padding = 10;<br>
<br>
dataprepro_syn = ft_preprocessing(cfg);<br>
<br>
<br>
The pad of 10 is the same as another already published study that used the<br>
same task.<br>
<br>
<br>
Attached is a picture of the problem (blu is baseline, red is stimulus).<br>
This is the result of multitepering (dpss).<br>
<br>
<br>
Thanks for your help,<br>
<br>
Davide<br>
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End of fieldtrip Digest, Vol 11, Issue 3<br>
****************************************<br>
</blockquote></div><br><br clear="all"><br>-- <br>Stephen Politzer-Ahles<br>University of Kansas<br>Linguistics Department<br><a href="http://www.linguistics.ku.edu/">http://www.linguistics.ku.edu/</a><br>