<div dir="ltr"><div class="gmail_default" style="color:rgb(51,51,153)">Much appreciated Jeff, that should work as ideal solution. It's curious that no one seems to have done it yet. There are a few methodological articles out there that look at subsets of 256 and there relations to 10-5 and other location systems. Yes in my experience 128 to 32, and 64 to 32 is easier to do, and the 256 to 128 is more difficult.</div><div class="gmail_default" style="color:rgb(51,51,153)"><br></div><div class="gmail_default" style="color:rgb(51,51,153)">EGI did not have a working solution/match comparing 128 and 256, but provides the 128 and 256 channel locations, placards, and 256/128 10-10 locations tech note.</div><div class="gmail_default" style="color:rgb(51,51,153)"><br></div><div class="gmail_default" style="color:rgb(51,51,153)">In general, a manual solution is workable if one has the 128 and 256 placards (both on web and from egi support), and the EGI tech note on 10-10 locations of 256 and 128 channels. The placards are easily found googlable and at EGI's knowledge center, which includes the tech note named as below.</div><div class="gmail_default" style="color:rgb(51,51,153)">relating-the-hcgsn-sensor-posi<wbr>tions-to-the-10-10-internation<wbr>al-electrode-placement-system<br></div><div class="gmail_default" style="color:rgb(51,51,153)"><br></div><div class="gmail_default" style="color:rgb(51,51,153)"><br></div><div class="gmail_default" style="color:rgb(51,51,153)"><br></div><div class="gmail_default" style="color:rgb(51,51,153)"><br></div><div class="gmail_default" style="color:rgb(51,51,153)"><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Jul 17, 2017 at 6:47 PM, K Jeffrey Eriksen <span dir="ltr"><<a href="mailto:eriksenj@ohsu.edu" target="_blank">eriksenj@ohsu.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">My 2 cents worth:<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Because of the geodesic (and in general spherical) layout of the electrodes, there is a very nice spatial down-sampling from 256 to 64, or from 128 to 32 (that
is by a factor of 4). Going from 256 to 128 is problematic spatially. If possible I suggest spatially interpolating the 256 channel data to the exact 128 channel locations.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">-Jeff Eriksen<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> eeglablist [mailto:<a href="mailto:eeglablist-bounces@sccn.ucsd.edu" target="_blank">eeglablist-bounces@scc<wbr>n.ucsd.edu</a>]
<b>On Behalf Of </b>Tarik S Bel-Bahar<br>
<b>Sent:</b> Sunday, July 16, 2017 2:19 PM<br>
<b>To:</b> eeglablist<br>
<b>Cc:</b> Support Team<br>
<b>Subject:</b> [Eeglablist] EGI 256 to 128 channels ?<u></u><u></u></span></p><div><div class="m_7306224153966575493h5">
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#333399">Greetings,<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="color:#333399">Does anyone have (or know of) a list of which EGI 256 hydrocel channels
<u></u><u></u></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#333399">that match up with the EGI 128 hydrocel channels ?<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="color:#333399">We're basically looking for the best possible match,<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="color:#333399">and a list of which channels from the 256 layout to keep<u></u><u></u></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#333399">in order to get as close as possible to the 128 channel layout.<u></u><u></u></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#333399">Thanks very much for any info that is available!<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="color:#333399">PS. we are doing this somewhat manually/visually at this time,<u></u><u></u></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#333399">and we already have access to the 10-10 correspondences tech note from EGI.<br>
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