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<p>Hi Alessandra,</p>
<p>we don't have coil models for Nextim coils. If the company is
willing to share detailed information about the coil geometry, we
can likely help you to get a reasonable model, though. <br>
</p>
<p>Regarding the coil position coordinates: Please use headreco, not
mri2mesh to create the head model, because headreco doesn't change
the header information of the T1 image. In addition, read the same
T1 image into the neuronavigation system. If this still results in
different positions for the coil center, then the Nexstim system
interally changes the coordinate system of the image. In that
case, we would need information from Nexstim on their internal
coordinate system to be able to resolve that issue.<br>
</p>
<p>Best regards,</p>
<p>Axel</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 08-06-2022 01:52, Alessandra
Dallavecchia wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAJzxtPq0i3wFkC8hs1QUSSewqaFbcZ3K66AUus3aZ9r0jT5sng@mail.gmail.com">
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<div class="gmail_default"
style="font-family:tahoma,sans-serif;font-size:small">Dear
all,</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif;font-size:small"><br>
</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif;font-size:small">I have
been working on trying to do some e-field simulations for our
TMS-EEG data, but have been running into a couple of issues. </div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif;font-size:small"><br>
</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif;font-size:small">We use a
Nexstim system (NBT 2.2), so my first question would be if
there was a reasonable approximation for a coil configuration
file that I could use, or how I might be able to create one
specific to the Nexstim figure-8 coil. </div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif;font-size:small"><br>
</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif;font-size:small">My
second question is in regards to the coil position
coordinates. Nexstim outputs three coordinates for coil
location, direction, and normal in mm. However, I've noticed
that these coordinates are wildly different from those that
SimNIBS gives me when I manually place a point on the GUI as
close to the center of the coil. Both are in mm and are in
subject space. I know that their coordinates line up with
FreeSurfer as I do source modeling for my EEG data, and I've
tried a number of permutations (e.g., switching x/y/z axes),
but nothing seems to get me close in SimNIBS to this actual
coil position when I use the Nexstim output coords.</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif;font-size:small"><br>
</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif;font-size:small"><b>Left
Parietal Stimulation Site from the Nexstim Neuronavigation</b></div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif;font-size:small"><img
src="cid:part1.Gd3fKxsu.OgdMjBET@drcmr.dk" alt="Coil
direction.png" style="margin-right: 0px;" class=""
width="487" height="314"></div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif;font-size:small"><span
style="font-family:Arial,Helvetica,sans-serif"><br>
</span></div>
<div class="gmail_default" style="font-size:small"><font
face="tahoma, sans-serif"><b>Similar Coil Position in the
SimNIBS GUI:</b></font></div>
<div class="gmail_default" style="font-size:small"><span
style="font-family:Arial,Helvetica,sans-serif"></span><br>
</div>
<img src="cid:part2.0UaYuc0L.QpLv2Bkt@drcmr.dk" alt="Coil Pos
SimNIBS.png" class="" width="542" height="481">
<div><br>
</div>
<div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif;font-size:small">Thank
you,</div>
<br>
<div>
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data-smartmail="gmail_signature">
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<div dir="ltr">
<div dir="ltr">
<div dir="ltr">
<div dir="ltr">
<div dir="ltr">
<div><i>--</i></div>
<div><b>Alessandra DallaVecchia, M.A.</b></div>
<div>PhD candidate, Cognitive Neuroscience</div>
<div>UCLA Department of Psychology</div>
<div>She/her</div>
<div><br>
</div>
<div><i>If this email finds you outside of
your normal business hours, please do
not feel obligated to reply and feel
free to respond when you're next
working or in front of a computer.</i></div>
</div>
</div>
</div>
</div>
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<br>
<fieldset class="moz-mime-attachment-header"></fieldset>
<pre class="moz-quote-pre" wrap="">_______________________________________________
Simnibs-discuss mailing list
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<a class="moz-txt-link-freetext" href="https://mailman.drcmr.dk/mailman/listinfo/simnibs-discuss">https://mailman.drcmr.dk/mailman/listinfo/simnibs-discuss</a>
</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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