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<p>Hi,</p>
<p>yes, it's for a current flow of 1A. The origin and coil
orienations are defined by the header information in the nifti
(the qform/sform matrices - please keep them identical to avoid
weird behaviors). It's a 6 DoF transformation between voxel
indices and real world coordinates (in mm).<br>
</p>
<p><br>
</p>
<p>Best regards,</p>
<p>Axel</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 20-05-2022 10:57, Andres Carvallo
Pecci wrote:<br>
</div>
<blockquote type="cite"
cite="mid:1420317107.653702.1653037047817.JavaMail.zimbra@umontpellier.fr">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div style="font-family: sans serif; font-size: 12pt; color:
#000000">
<div>Hello,</div>
<div><br>
</div>
<div>I'm trying to model <span style="color: #000000;
font-family: 'sans serif'; font-size: 16px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: 400; letter-spacing: normal; orphans:
2; text-align: start; text-indent: 0px; text-transform:
none; white-space: normal; widows: 2; word-spacing: 0px;
-webkit-text-stroke-width: 0px; background-color: #ffffff;
text-decoration-thickness: initial; text-decoration-style:
initial; text-decoration-color: initial; display: inline
!important; float: none;" data-mce-style="color: #000000;
font-family: 'sans serif'; font-size: 16px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: 400; letter-spacing: normal; orphans:
2; text-align: start; text-indent: 0px; text-transform:
none; white-space: normal; widows: 2; word-spacing: 0px;
-webkit-text-stroke-width: 0px; background-color: #ffffff;
text-decoration-thickness: initial; text-decoration-style:
initial; text-decoration-color: initial; display: inline
!important; float: none;">helmoltz-like </span>coil
(A-field) in matlab and then transfer it to simnibs in the
form of a compressed Nifti file.</div>
<div><br>
</div>
<div>I did a discretization 2.5 mm as suggested in the
"Deng_Brain_Stim_2013" document (attached). My questions are
the following:</div>
<div><br>
</div>
<div>1) The A-field is calculated with a electric current equal
to 1A?</div>
<div>2) In the simnibs program, where is the origin coordinate
with respect to the brain?</div>
<div><br>
</div>
<div>My magnetic exposure is a helmoltz-like coil, stimulating
the entire brain, but it seems that in my simnibs simulation,
I am doing something wrong given that the simulated induced
E-field is localized in Cz.</div>
<div> <img src="cid:part1.3YNq1A4Q.tjiHlXIQ@drcmr.dk"
data-mce-src="imap://axelt@imap.drcmr.dk:993/fetch%3EUID%3E.INBOX%3E93212?header=quotebody&part=1.1.2.2&filename=Screen%20Shot%202022-05-20%20at%2010.49.21%20AM.png"
class="" width="382" height="272"><img
src="cid:part2.xF2gs2KK.GkeE1DBj@drcmr.dk"
data-mce-src="imap://axelt@imap.drcmr.dk:993/fetch%3EUID%3E.INBOX%3E93212?header=quotebody&part=1.1.2.3&filename=Screen%20Shot%202022-05-20%20at%2010.46.39%20AM.png"
class="" width="241" height="268"></div>
<div>Thank you for your help.</div>
<div>Andres </div>
</div>
<br>
<fieldset class="moz-mime-attachment-header"></fieldset>
<pre class="moz-quote-pre" wrap="">_______________________________________________
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</pre>
</blockquote>
<pre class="moz-signature" cols="72">--
Dr. Axel Thielscher
Professor of Neurophysics and Neuroimaging
Danish Research Center for Magnetic Resonance
Copenhagen University Hospital Hvidovre
DK-2650 Hvidovre, Denmark
<a class="moz-txt-link-abbreviated" href="http://www.drcmr.dk">www.drcmr.dk</a>
&
Department of Health Technology
Technical University of Denmark
DK-2800 Kgs. Lyngby
<a class="moz-txt-link-freetext" href="http://www.healthtech.dtu.dk/">http://www.healthtech.dtu.dk/</a></pre>
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