<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">
Hi Jinwen,
<div class=""><br class="">
</div>
<div class="">The physical units of the lead field are units-of-the-stuff-you-measure-with-your-measurement-device / units-of-dipole-moment.</div>
<div class=""><br class="">
</div>
<div class="">Thus - for EEG - this will be something like V / Am. <br class="">
<div><br class="">
</div>
<div>I don’t think I fully understand your question: do you mean with ’the resulting magnitude of lead field was 10^-5’ that the resulting signal was of magnitude 10^-5 (which for EEG would be 10 microvolts)? I would say that this does not sound too bad.</div>
<div><br class="">
</div>
<div>Best wishes,</div>
<div>Jan-Mathijs</div>
<div><br class="">
</div>
<div><br class="">
</div>
<div><br class="">
<blockquote type="cite" class="">
<div class="">On 20 Oct 2021, at 10:14, Jinwen Wei via fieldtrip <<a href="mailto:fieldtrip@science.ru.nl" class="">fieldtrip@science.ru.nl</a>> wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<div dir="ltr" class="">
<div dir="ltr" class="">Dear all,
<div class=""><br class="">
</div>
<div class="">My name is Jinwen and I am conducting forward modelling for EEG source reconstruction following <i class=""><a href="https://urldefense.com/v3/__https://www.fieldtriptoolbox.org/workshop/oslo2019/forward_modeling/__;!!HJOPV4FYYWzcc1jazlU!oldn94sFtU6sSZ3RhSg1GJfmLd1KDLSj8B0iy5NPqJS8fTZkip453A0marDA7JmkgmcppbJRrIlKPpA$" class="">https://www.fieldtriptoolbox.org/workshop/oslo2019/forward_modeling/</a></i>.
I have a question about the magnitude of lead field matrix.</div>
<div class=""><br class="">
</div>
<div class="">According to the tutorial, the leadfield describes what would be seen at the sensor level given that a source was active with a given current (1 Am). In the ending part of the tutorial, a realistic source current of 100 nAm was used to plot the
lead field and the resulting magnitude of lead field was 10^-5. That is to say, the original lead field had a magnitude of 10^2 because 10^2 *100*10^-9 = 10^-5. However, how come the original lead field has such a huge magnitude. Actually, when I modelled
the lead field using standard BEM, I found the magnitude of the original lead field was quite small, like 10^-5. So I am wondering what magnitude of the original lead field is.</div>
<div class=""><br class="">
</div>
<div class="">Best regards,</div>
<div class="">Jinwen</div>
</div>
</div>
_______________________________________________<br class="">
fieldtrip mailing list<br class="">
<a href="https://mailman.science.ru.nl/mailman/listinfo/fieldtrip" class="">https://mailman.science.ru.nl/mailman/listinfo/fieldtrip</a><br class="">
https://urldefense.com/v3/__https://doi.org/10.1371/journal.pcbi.1002202__;!!HJOPV4FYYWzcc1jazlU!oldn94sFtU6sSZ3RhSg1GJfmLd1KDLSj8B0iy5NPqJS8fTZkip453A0marDA7JmkgmcppbJRGYbBKX4$
<br class="">
</div>
</blockquote>
</div>
<br class="">
</div>
</body>
</html>