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Dear Dorte,<br>
<br>
we fixed this problem recently. It was due to the eeglab2fieldtrip
function. Just replace it in the Fieldtrip folder.<br>
<br>
Best,<br>
<br>
Arno<br>
<br>
Dörte Spring wrote:
<blockquote cite="mid455A31D2.1030201@nat.uni-magdeburg.de" type="cite">Dear
Stefan and EEGLABler,
<br>
<br>
thanks so much for the immediate and detailed answer as well as the
<br>
attached mapping code.
<br>
<br>
Nevertheless, I have detected another problem doing the dipols on raw
<br>
ERPs. As I tried to follow the EEGLAB manual instructions I noticed
that
<br>
ICA weights are still necessary, at least to determine the spherical
<br>
model for dipfit. Is that correct?
<br>
However, then I tried to use ICAs for this model specification.
<br>
Unfortunately, it did not work. EEGLAB (5.03; in Matlab 7.0.4.352 (R14)
<br>
Service Pack 2) gave an error (see attached pdf - first page) in the
<br>
second step "Coarse fit". Thus, I dared bravely to run the script for
<br>
ERP dipoles described in the manual. Thereby, I realized that some of
<br>
the needed functions like "dipfit_erpeeg.m" were missing. I put a
<br>
screen shot of all my plugins/dipfit2.0 and all function files in the
<br>
attached pdf as well (second page). Or could I find this missing file
<br>
maybe elsewhere? At first I thought my eeglab version is not properly
<br>
installed, but nothing changed with a new download and installation.
<br>
<br>
<br>
I really appreciate any tips.
<br>
<br>
Best regards,
<br>
<br>
Doerte
<br>
<br>
<br>
<br>
Stefan Debener wrote:
<br>
<blockquote type="cite">Dear Doerte,
<br>
<br>
yes, it's all possible with EEGLAB, but requires some scripting skills.
So, the easiest way to do ERP statistics may be to export your ERP data
to SPSS or SAS and define time windows, peak latencies etc. there. To
do this, go to 'File' > 'Export' > 'Export data and ICA activity
to text file', and tick the box 'Export ERP average instead of single
trials'. This is also the easiest way to export your ERP data into
other software such as BESA. Also, check out the EEGLAB plug-ins (e.g.
those from Andreas Widmann), some have been designed specifically to
ease ERP analysis and may come with a nice gui.
<br>
<br>
Regarding the maps, I have attached a little piece of code below. This
code assumes that you have loaded two datasets into EEGLAB (dataset
1=condition 1, dataset 2=condition 2), that these two conditions have
the same number of frames per epoch (and same epoch start-stop time)
and that you want to plot maps for a mean interval (t1 to t2) maps. It
plots the map for each condition (average across interval), and the
resulting difference map. Look up the help message of topoplot.m for
more options on how to plot nice maps. Also, be careful with the
interpretation of difference maps. We always plot the difference map
together with the single condition maps. Difference maps can be quite
misleading, in particular if the two maps you are subtracting are
different in 'shape', and not only in 'strength' (amplitude).
<br>
<br>
If you want to do a dipole source analysis of ERPs or ERP difference
maps instead of ICA weights, you can do this with EEGLAB/DIPFIT as
well. Again, it requires some scripting, and is described in detail in
the EEGLAB manual. You may also download Patrick Berg's DipoleSimulator
(<a class="moz-txt-link-abbreviated" href="http://www.besa.de">www.besa.de</a>), it's a powerful and easy to use free windows software
allowing you to play a bit with how different source configurations
(number, location, orientation) affect the resulting voltage maps -
very instructive.
<br>
<br>
Best,
<br>
Stefan
<br>
<br>
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
<br>
%start-stop interval (in ms)
<br>
t1 = 200;
<br>
t2 = 300;
<br>
<br>
% find corresponding data frames. Code adapted from
<br>
% Robert Oostenvelds function nearest.m
<br>
% Copyright (C) 2002, Robert Oostenveld
<br>
[mindist, t1] = min(abs(ALLEEG(1).times - t1));
<br>
[mindist, t2] = min(abs(ALLEEG(1).times - t2));
<br>
<br>
% voltage for each electrode, mean across interval and trials
<br>
data1 = mean(mean(ALLEEG(1).data(:,t1:t2,:),3),2);
<br>
data2 = mean(mean(ALLEEG(2).data(:,t1:t2,:),3),2);
<br>
<br>
%map scale (in uV)
<br>
scale = [-4 4];
<br>
<br>
%plot figure
<br>
figure;
<br>
subplot(1,3,1);
<br>
topoplot(data1,EEG.chanlocs, 'maplimits', scale);
<br>
title('cond 1');
<br>
subplot(1,3,2);
<br>
topoplot(data2,EEG.chanlocs, 'maplimits', scale);
<br>
title('cond 2');
<br>
subplot(1,3,3);
<br>
topoplot([data1-data2],EEG.chanlocs, 'maplimits', scale);
<br>
title('difference: 1-2');
<br>
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
Dörte Spring wrote:
<br>
<blockquote type="cite">Dear EEGLABler,
<br>
<br>
I'm right now at the point in data analysis where I'd like to do some
<br>
statistical analyis as well. My interests lies on ERP and their
<br>
components rather than ICA components. Thus, I was wondering whether
<br>
there are included some tools for this in EEGLAB that I could use. Im
<br>
interested in things like differences in peak amplitude, or peak
<br>
latencies for specified ERP components in a certain time window (by
<br>
ANOVA for example).
<br>
<br>
I also would like to support significant results of this analysis by
<br>
scalp maps of the analyzed component's difference wave. Is there a way
<br>
in EEGLAB, too, to do that? So far I only have seen the option to topo
<br>
plot a component of a single condition, but not the difference
potential
<br>
between two conditions.
<br>
<br>
Because all good things come in three, I have another question: Can one
<br>
also determine dipoles in EEGLAB withouth ICAs by just using the
<br>
difference wave potential in a specific time frame?
<br>
<br>
Any suggestions are welcome.
<br>
<br>
Best regards,
<br>
<br>
Doerte
<br>
<br>
</blockquote>
<br>
<br>
<br>
<br>
</blockquote>
<br>
<pre wrap="">
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</blockquote>
<br>
<br>
<div class="moz-signature">-- <br>
<br>
<b><font face="Arial,Helvetica"><font size="+1">Arnaud Delorme, Ph.D.</font></font></b>
<br>
<font face="Arial,Helvetica"><font size="+1"><font color="#3333ff">Swartz
Center for Computational Neuroscience,</font> <font color="#3333ff">INC,
University of San Diego California</font></font></font>
<br>
La Jolla, CA92093-0961, USA
<p><font face="Arial,Helvetica"><b>Tel</b> :<i>(+1)-858-458-1927 ext 15</i></font>
<br>
<font face="Arial,Helvetica"><b>Fax</b> :<i>(+1)-858-458-1847</i></font>
<br>
<font face="Arial,Helvetica"><b>Web page</b>: <a
href="http://www.sccn.ucsd.edu/%7Earno">sccn.ucsd.edu/~arno</a></font>
<br>
<font face="Arial,Helvetica"><b>To think upon</b>:</font></p>
<blockquote><dt><font face="Arial,Helvetica"> Truth is that which
works.
<font size="-5"><br>
<br>
</font></font></dt>
<dd><font face="Arial,Helvetica"><i>Buddha</i></font></dd>
</blockquote>
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