<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Thanks Manos,<div><div>You are correct, but setting a low threshold also seems to detect things that are not eyeblinks, such as alpha noise, fluctuating channels, HF noise, etc. When I set a low threshold for detecting eyeblinks and it seems to detect them just fine. However, it also marks any epoch for rejection in which any one of the scalp channels fluctuates above that threshold. I am looking for a way to either restrict the thresholded fluctuation detection to the EOG channels or set a low threshold to EOG channels and a less conservative threshold to the scalp electrodes. </div><div>Brion</div><div><br><div><div>On Oct 22, 2008, at 4:51 PM, Klados Manousos wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">Dear Brion<br><br>If you search in literature there exist a certain paper which suggest that eye blink's voltage is larger than 50 ΞΌV. So you can put a threshold of 50ΞΌV for eye blinks. If i understand you you need an automatic procedure to reject contaminated epochs. One very easy algorithm is to find epochs with values larger than 50 ΞΌV and exclude them for your study. I can't understand the reason you need different threshold for different channels. You can indetify contaminated epochs from one signal and in the others the epochs have to be the same...correct me if i uderstood wrong.<br> <br>Greetings<br>Manos<br><br><div class="gmail_quote">2008/10/22 Brion Woroch <span dir="ltr"><<a href="mailto:bworoch2@illinois.edu">bworoch2@illinois.edu</a>></span><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> Hello,<br> I am looking for a way to set the threshold for the "detection of<br> extremely large fluctuations" in the automatic epoch rejection<br> differentially for different channels. I would like to set one<br> threshold for EOG channels and another for scalp electrodes. Does<br> anybody know how I can accomplish this? Thanks in advance.<br> Brion Woroch<br> <br> _______________________________________________<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> </blockquote></div><br><br clear="all"><br>-- <br>Klados A. Manousos<br>Graduate Student, Research Assistant<br>Lab of Medical Informatics, Medical School<br>Aristotle University of Thessaloniki<br>Thessaloniki, Greece<br> _________________________________________________<br>Tel: +30-2310-999332<br>Website :<br><a href="http://lomiweb.med.auth.gr/gan/index_files/Page1269.htm">http://lomiweb.med.auth.gr/gan/index_files/Page1269.htm</a> <br><br> </blockquote></div><br></div></div></body></html>