<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="">Dear Sophia,<div class=""><br class=""></div><div class="">Fieldtrip comes with a number of precomputed Headmodels as well as standard MRIs which you can use (take a look into the „forward“-folder in the FT directory).</div><div class="">You just have to make sure, your electrodes fit to the headmodels, but you would have to do this with a „real“ MRI as well.</div><div class=""><br class=""></div><div class="">Good luck,</div><div class=""><br class=""></div><div class="">Julian<br class=""><div><br class=""><blockquote type="cite" class=""><div class="">Am 12.12.2017 um 17:24 schrieb Irene Sophia Mayer <<a href="mailto:mi_mayer@gmx.de" class="">mi_mayer@gmx.de</a>>:</div><br class="Apple-interchange-newline"><div class=""><div class=""><div style="font-family: Verdana;font-size: 12.0px;" class=""><div class="">Dear Fieldtrippers,</div>
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<div class="">I am attempting to do source reconstruction with Fieldtrip for the first time. I have EEG data but no MRI, just measurements of the electrode positions (with Zebris). However, I got already stuck at creating the forward model.</div>
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<div class="">Do I need to prepare my own sourcemodel with ft_prepare_sourcemodel or can I use the default options in ft_prepare_leadfield?</div>
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<div class="">All tutorials for creating a headmodel use an MRI, how can I do it without MRI images of my subjects?</div>
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<div class="">I have tried to use ft_prepare_headmodel with</div>
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<pre class=""><span style="font-size:12px;" class=""><span style="font-family: Courier New, Courier, monospace;" class="">headmodel = ft_prepare_headmodel(cfg, elec) with the output of <a href="http://www.fieldtriptoolbox.org/reference/ft_read_sens" class=""><font color="green" class="">FT_READ_SENS </font></a>headmo</span></span></pre>
<div class=""><span style="font-size:12px;" class=""><span style="font-family: Courier New, Courier, monospace;" class="">elec =</span></span></div>
<div class=""><span style="font-size:12px;" class=""><span style="font-family: Courier New, Courier, monospace;" class=""> chanpos: [62x3 double]<br class="">
elecpos: [62x3 double]<br class="">
label: {62x1 cell}<br class="">
type: 'eeg1005'<br class="">
unit: 'mm'</span></span></div>
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<div class="">Unfortunately, it first told me: <span style="color:#ff0000;" class="">Either a segmentated MRI or data with closed triangulated mesh is required as data<br class="">
input for the bemcp, dipoli or openmeeg method</span>, and when I tried other methods, I got: <span style="color:#ff0000;" class="">The data input might already be a sensor description. Reference to non-existent field 'outputfile'</span></div>
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<div class="">I would be thankful for tips on how to do this!</div>
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<div class="">Best,</div>
<div class="">Sophia</div>
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