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<p class="MsoNormal"><span lang="EN-GB">Dear fieldtripers, <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I have experienced a problem with ft_sourcegrandaverage and the calculation of my grid and I want to ask for help.
<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB">The error I get is the following
</span><span lang="EN-GB" style="font-size:10.0pt;font-family:"Courier New";color:#A020F0">:</span><span lang="EN-GB" style="font-size:10.0pt;font-family:"Courier New";color:red">different grid locations in source reconstructions.<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB" style="font-size:10.0pt;font-family:"Courier New";color:red"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I will describe briefly the processing to give you a better idea about my error.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">For every subject I have 6 conditions and I want to average all subjects per condition.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">After preprocessing I calculate the covariance matrix and then I use the MUSIC algorithm for my sources.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">For the grid calculation I use a default MRI a default VOL and a default electrodes’ positions.<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB">However for every subject the grid is not identical since
</span><span lang="EN-GB" style="font-size:10.0pt;font-family:"Courier New";color:black">cfg.channel
</span><span lang="EN-GB" style="font-size:10.0pt;color:black">in ft_prepare_leadfield
</span><span lang="EN-GB" style="color:black">is dependent on the channels I’ve discarded as noisy during the preprocessing.
<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB" style="color:black">By the way for the grid calculation I had to change the order of cfg.elec because it didn’t agree with the order of cfg,channel in my data.<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB" style="color:black">So apparently I end up with a different grid for every subject but still I want to average all of them per condition.<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB" style="color:black"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB" style="color:black">Do I have to use another function to average my sources in this case?<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB" style="color:black">Because the grid would never be identical among subjects.<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB" style="color:black"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB" style="color:black"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB" style="color:black">I hope somebody out there experienced that before and can probably help me.
<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB" style="color:black">Thank you.<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB" style="color:black"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB" style="color:black">Konstantina [Nadia] Kalogianni<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB" style="color:black">PhD candidate, TU Delft<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-GB" style="color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
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