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<div class="moz-cite-prefix">Hi John,<br>
<br>
I would assume it is the pruning for the "Venant condition", i.e.,
that all dipole positions are close to a vertex <br>
whose neighbors are all in grey matter, because they get the
monopolar weights that approximate best<br>
the given dipolar moment. Check e.g. this one<br>
<a class="moz-txt-link-freetext" href="https://urldefense.com/v3/__https://www.sciencedirect.com/science/article/abs/pii/S1053811919306202?via*3Dihub__;JQ!!HJOPV4FYYWzcc1jazlU!4DOkcvTkP8Z9h_Yzt9uN57aiBPGOzIlZdiq7PXavgWu2nBGVh0tRGmOObbdzcvD0VPSgLcWYRDApReSO059VXIwT8NHMCMF2xSWo_A$">https://www.sciencedirect.com/science/article/abs/pii/S1053811919306202?via%3Dihub</a><br>
<br>
@Johannes: Did you implement the "ft_inside_headmodel.m" and do
you agree?<br>
<br>
We are now investigating a new FEM source model, the "localized
subtraction approach"<br>
<a class="moz-txt-link-freetext" href="https://urldefense.com/v3/__http://www.sci.utah.edu/*wolters/PaperWolters/2022/HoeltershinkenEtAl_Biosignale2022.pdf__;fg!!HJOPV4FYYWzcc1jazlU!4DOkcvTkP8Z9h_Yzt9uN57aiBPGOzIlZdiq7PXavgWu2nBGVh0tRGmOObbdzcvD0VPSgLcWYRDApReSO059VXIwT8NHMCMHvhmzaGw$">http://www.sci.utah.edu/~wolters/PaperWolters/2022/HoeltershinkenEtAl_Biosignale2022.pdf</a><br>
where this "pruning" might be alliviated or not be needed at all,
as long as the source is in GM.<br>
<br>
Best regards<br>
Carsten<br>
<pre class="moz-signature" cols="72">--
Prof. Dr.rer.nat. Carsten H. Wolters
University of Münster
Institute for Biomagnetism and Biosignalanalysis
Malmedyweg 15
48149 Münster, Germany
Phone:
+49 (0)251 83 56904
+49 (0)251 83 56865 (secr.)
Fax:
+49 (0)251 83 56874
Email: <a class="moz-txt-link-abbreviated" href="mailto:carsten.wolters@uni-muenster.de">carsten.wolters@uni-muenster.de</a>
Web: <a class="moz-txt-link-freetext" href="https://urldefense.com/v3/__https://campus.uni-muenster.de/biomag/das-institut/mitarbeiter/carsten-wolters/__;!!HJOPV4FYYWzcc1jazlU!4DOkcvTkP8Z9h_Yzt9uN57aiBPGOzIlZdiq7PXavgWu2nBGVh0tRGmOObbdzcvD0VPSgLcWYRDApReSO059VXIwT8NHMCMGyB_9iWw$">https://campus.uni-muenster.de/biomag/das-institut/mitarbeiter/carsten-wolters/</a></pre>
<br>
<br>
Am 13.02.23 um 19:52 schrieb Richards, John via fieldtrip:<br>
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<p class="MsoNormal">In on of the source analysis modules,
likely for the simbio lead field computation, I get the
message below about pruning elements of the head model. Does
anyone know what this means? I don’t think I have seen it
before.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">John <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">creating sourcemodel based on user
specified 3D grid<o:p></o:p></p>
<p class="MsoNormal">using electrodes specified in the
configuration<o:p></o:p></p>
<p class="MsoNormal">selecting dipole positions inside the 'gm'
tissue<o:p></o:p></p>
<p class="MsoNormal">pruning headmodel volume elements from
1572480 to 450494 (29%)<o:p></o:p></p>
<p class="MsoNormal">pruning headmodel vertices from 262013 to
159509 (61%)<o:p></o:p></p>
<p class="MsoNormal">pruning dipole positions from 1887681 to
1759824 (93%)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This is in the ft_inside_headmodel, both
inverse and forward<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">./inverse/private/ft_inside_headmodel.m:
fprintf('pruning headmodel volume elements from %d to %d
(%d%%)\n', numhex, sum(insidehex),
round(100*sum(insidehex)/numhex));<o:p></o:p></p>
<p class="MsoNormal">./inverse/private/ft_inside_headmodel.m:
fprintf('pruning headmodel vertices from %d to %d (%d%%)\n',
numpos, sum(insidepos), round(100*sum(insidepos)/numpos));<o:p></o:p></p>
<p class="MsoNormal">./inverse/private/ft_inside_headmodel.m:
fprintf('pruning dipole positions from %d to %d (%d%%)\n',
numdip, sum(insidedip), round(100*sum(insidedip)/numdip));<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">./forward/ft_inside_headmodel.m:
fprintf('pruning headmodel volume elements from %d to %d
(%d%%)\n', numhex, sum(insidehex),
round(100*sum(insidehex)/numhex));<o:p></o:p></p>
<p class="MsoNormal">./forward/ft_inside_headmodel.m:
fprintf('pruning headmodel vertices from %d to %d (%d%%)\n',
numpos, sum(insidepos), round(100*sum(insidepos)/numpos));<o:p></o:p></p>
<p class="MsoNormal">./forward/ft_inside_headmodel.m:
fprintf('pruning dipole positions from %d to %d (%d%%)\n',
numdip, sum(insidedip), round(100*sum(insidedip)/numdip));<o:p></o:p></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:Consolas;color:black;mso-ligatures:none">***********************************************<br>
John E. Richards<br>
Carolina Distinguished Professor<br>
Department of Psychology<br>
University of South Carolina<br>
Columbia, SC 29208<br>
Dept Phone: 803 777 2079<br>
Fax: 803 777 9558<br>
Email: </span><span style="color:#1F497D;mso-ligatures:none"><a
href="mailto:richards-john@sc.edu" moz-do-not-send="true"><span
style="font-size:10.0pt;font-family:Consolas;color:#0563C1">richards-john@sc.edu</span></a></span><u><span
style="font-size:10.0pt;font-family:Consolas;color:blue;mso-ligatures:none"><br>
</span></u><span
style="font-size:10.0pt;font-family:Consolas;color:black;mso-ligatures:none"><a
href="https://urldefense.com/v3/__https://jerlab.sc.edu__;!!HJOPV4FYYWzcc1jazlU!-J1ZRygBFwHfm02-qbAb5IRd5vZq6CUPGnlnoLEy8Y7Ar0w4fUhpC1FPgOompIoyFW2guQl_5gKtR0mQnk8D-BQRrlgo$"
moz-do-not-send="true"><span style="color:#0563C1">https://jerlab.sc.edu</span></a><br>
***********************************************<br>
<br>
</span><span style="mso-ligatures:none"><o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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