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<div class="moz-cite-prefix">Dear Ravi,<br>
<br>
1) You can use the pure SimBio-code from <br>
<a class="moz-txt-link-freetext" href="https://www.mrt.uni-jena.de/simbio/index.php/Main_Page">https://www.mrt.uni-jena.de/simbio/index.php/Main_Page</a><br>
to treat WM anisotropy.<br>
While it would in principle also be possible to use anisotropic
conductivities with FieldTrip-SimBio, <br>
this is currently not implemented using ft_prepare_headmodel.
Johannes (in CC), who implemented <br>
Fieldtrip-SimBio, answered a same question by Junjie Wu in March
2018: <br>
"Depending on your matlab skills and your available time, I could
help you to give it a <br>
try though. It should be possible with using some direct function
calls instead of the high-level fieldtrip-functions."<br>
<br>
2) We recommend <br>
<a class="moz-txt-link-freetext" href="http://www.sci.utah.edu/~wolters/PaperWolters/2012/RuthottoEtAl_PhysMedBiol_2012.pdf">http://www.sci.utah.edu/~wolters/PaperWolters/2012/RuthottoEtAl_PhysMedBiol_2012.pdf</a><br>
on individual data. I could imagine that an atlas does a
reasonable job w.r.t. the main<br>
bigger fiber tracts such as corpus callosum or pyramidal tracts,
but that the finer details<br>
in the cortices are individual. We always measure T1, T2 and DTI
from each subject<br>
and I personally do not have experience with such a group-level
anisotropy compared <br>
to the individual one. Might be interesting to hear from others
what they think!?<br>
<br>
BR<br>
Carsten<br>
<br>
<br>
<br>
Am 25.10.18 um 23:05 schrieb Ravi Mill:<br>
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Dear Fieldtrippers</p>
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I have applied the FEM simbio head modeling pipeline
implemented in Fieldtrip to my EEG data. <span>My
understanding is that this pipeline assumes isotropic
conductivities for 5 head compartments (as specified by
cfg.conductivity in ft_prepare_headmodel). </span>After
reading some papers (e.g. Vorwerk et al 2014 <a
href="https://doi.org/10.1016/j.neuroimage.2014.06.040"
class="OWAAutoLink" id="LPlnk216235" previewremoved="true"
moz-do-not-send="true">https://doi.org/10.1016/j.neuroimage.2014.06.040</a>),
it seems like incorporating white matter conductivity
anisotropy has a relatively small albeit significant effect on
the source solution. I am interested in comparing FEM results
when treating white matter as anisotropic. <span
style="font-size:12pt">My questions are as follows:</span></p>
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<span style="font-size:12pt"><br>
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<ol style="margin-bottom:0px; margin-top:0px">
<li style="">Is there a way to implement the FEM simbio head
model whilst treating WM as anisotropic within Fieldtrip? If
so, how would one do this (or are there any resources
available that demonstrate this)?</li>
<li style="">From previous papers and some simbio
documentation (<a
href="https://www.mrt.uni-jena.de/simbio/index.php/SIMBIO/Releasenotes/Examples"
class="OWAAutoLink" id="LPlnk493580" previewremoved="true"
moz-do-not-send="true">https://www.mrt.uni-jena.de/simbio/index.php/SIMBIO/Releasenotes/Examples</a>)
it seems like diffusion MRI data is required to calculate
the WM conductivity for each individual subject. I only have
T1 and T2 scans for my subjects. So would it be possible to
use WM anisotropic information obtained from some kind of
diffusion MRI group average/atlas instead (accepting some
loss in subject-level precision)? If so, does such a group
average/atlas exist?</li>
</ol>
<br>
<p style="margin-top:0px; margin-bottom:0px">Any help would be
greatly appreciated!</p>
<p style="margin-top:0px; margin-bottom:0px"><br>
</p>
<p style="margin-top:0px; margin-bottom:0px">Thanks</p>
<p style="margin-top:0px; margin-bottom:0px">Ravi</p>
<br>
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<pre class="moz-quote-pre" wrap="">_______________________________________________
fieldtrip mailing list
<a class="moz-txt-link-freetext" href="https://mailman.science.ru.nl/mailman/listinfo/fieldtrip">https://mailman.science.ru.nl/mailman/listinfo/fieldtrip</a>
<a class="moz-txt-link-freetext" href="https://doi.org/10.1371/journal.pcbi.1002202">https://doi.org/10.1371/journal.pcbi.1002202</a>
</pre>
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<br>
<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://campus.uni-muenster.de/biomag/das-institut/mitarbeiter/carsten-wolters/">https://campus.uni-muenster.de/biomag/das-institut/mitarbeiter/carsten-wolters/</a></pre>
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