Javier,<br>I would not recommend doing what you suggested. Alpha is extremely important and you should not remove it. Idle rhythms of the brain like alpha and mu are partially phase reset by stimuli, and this is in part what produces ERPs/ERFs. I think you are assuming a purely amplitude modulation theory for the generation of ERP/ERF, and even if that was in part true for some systems (e.g., auditory, since Tau rhythm is often absent in subjects), if you filter out 10Hz, you will not get the peaks at 100, 200, 300, etc, and completely destroy your data.<br>
Let's be clear the reason why ICA comes up better after 1Hz high pass filtering is that the very slow waves (<1Hz) seem to make all IC more dependent (i.e., they all go up and down together). That's not true for alpha.<br>
In any case, you can always do complex infomax ICA for single frequencies or Independent Vector Analysis for for spectral bands.<br>Hope this makes some sense,<br>Ret <br><br><br><div class="gmail_quote">On Thu, Oct 13, 2011 at 2:59 PM, Javier Lopez-Calderon <span dir="ltr"><<a href="mailto:javlopez@uc.cl">javlopez@uc.cl</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">If this would be true then this would certainly be a good way to remove alpha activity from bored subjects' EEG, for instance. We'd just need to band-pass filter the data between 8-12 Hz, run ICA, and do the trick with the unfiltered data...<br>
<br>
There should be something wrong with this rationale...right?<br>
<font color="#888888"><br>
Javier<br>
</font><div class="im"><br>
<br>
<br>
><br>
> BTW, someone else suggested using the 1-Hz high-pass cutoff, performing ICA, and then applying the component coefficients to the unfiltered data. That sounds like a great suggestion, although I don't know if there is a technical reason why it wouldn't work. Does anyone out there know if there would be a problem with this?<br>
><br>
> Steve<br>
<br>
<br>
</div><div><div></div><div class="h5">_______________________________________________<br>
Eeglablist page: <a href="http://sccn.ucsd.edu/eeglab/eeglabmail.html" target="_blank">http://sccn.ucsd.edu/eeglab/eeglabmail.html</a><br>
To unsubscribe, send an empty email to <a href="mailto:eeglablist-unsubscribe@sccn.ucsd.edu">eeglablist-unsubscribe@sccn.ucsd.edu</a><br>
For digest mode, send an email with the subject "set digest mime" to <a href="mailto:eeglablist-request@sccn.ucsd.edu">eeglablist-request@sccn.ucsd.edu</a><br>
</div></div></blockquote></div><br><br clear="all"><br>-- <br><span style="font-family:times new roman,serif">Rey R. Ramírez, Ph.D.</span><br style="font-family:times new roman,serif"><span style="font-family:times new roman,serif">MEG Brain Imaging Center</span><font style="font-family:times new roman,serif" face="verdana, arial, helvetica, sans-serif" size="2"><br>
Institute for Learning & Brain Sciences</font><font style="font-family:times new roman,serif" face="verdana, arial, helvetica, sans-serif" size="2"><br>Portage Bay Building<br>Box 357988<br>University of Washington<br>
Seattle, WA 98195-7988</font><br style="font-family:times new roman,serif"><span style="font-family:times new roman,serif">e-mail: </span><a style="font-family:times new roman,serif" href="mailto:rrramir@uw.edu" target="_blank">rrramir@uw.edu</a><font face="verdana, arial, helvetica, sans-serif" size="2"><br style="font-family:times new roman,serif">
<span style="font-family:times new roman,serif">Tel: (206) 543-6484 </span><br style="font-family:times new roman,serif"><span style="font-family:times new roman,serif">Fax: (206) 221-6472</span><br style="font-family:times new roman,serif">
<span style="font-family:times new roman,serif">Cell: (619) 709-3590</span><br></font><br>