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Dear Tom,<br>
<blockquote type="cite"
cite="mid1106743963.41f7929b4120a@www3.helsinki.fi">
<pre wrap="">Please may ask if there are functions to do this method for calculating
amplitudes in a given range in EEGLAB?
</pre>
</blockquote>
There is no such function in EEGLAB but if you write it, we will be
glad to integrate it.<br>
<blockquote type="cite"
cite="mid1106743963.41f7929b4120a@www3.helsinki.fi">
<pre wrap="">Alternatively, please is there a simple way to access the data structures
that store the ERPs used by pop_plotdata()?
</pre>
</blockquote>
The ERP can be calculated using this simple command<br>
<br>
erp = mean(EEG.data,3);<br>
<br>
(3 indicating that the average has to be performed on the 3rd dimension
of the data array which contains all the singles trials). To plot the
ERP for the first data channel, type<br>
<br>
figure; plot(EEG.times, erp);<br>
<br>
% The area between 62.5 and 67.5 ms could calculated using<br>
[tmp ind1] =min( abs( EEG.times - 62.5 ) ); % closest time index to
62.5 ms<br>
[tmp ind2] =min( abs( EEG.times - 67.5 ) ); % closest time index to
67.5 ms<br>
<br>
erp_interval = sum(erp(:, ind1:ind2));<br>
<br>
% if you want to smooth the data prior to computing the sum (filter
below 30 Hz), type in<br>
erp_smooth = eeg_filt(erp, EEG.srate, 0, 30);<br>
erp_interval = sum(erp_smooth(:, ind1:ind2));<br>
<br>
Hope this help,<br>
<br>
Arno<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"> If the book we are
reading does not wake us, as with a fist hammering on our skull, why
then do we read it? A book must be an ice-axe to break the sea frozen
inside us.
<font size="-5"><br>
<br>
</font></font></dt>
<dd><font face="Arial,Helvetica"><i>Frank Kafka</i></font></dd>
</blockquote>
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