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<p class="MsoNormal"><span lang="EN-US">Hi Fieldtrippers,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I have been trying to do a source analysis on my (resting-state) data using LCMV beamforming and as part of a sanity check, I wanted to plot the alpha power.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Using ft_sourceanalysis I get a source structure containing avg.pow and intuitively I expected this field to contain the averaged power of the time series. Therefore, I band-passed the data on the sensor level before
doing the LCMV source reconstruction.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Surprisingly however, when I used the resulting LCMV spatial filter to construct virtual channels and calculated the alpha power spectrum of the resulting time series using ft_freqanalysis, the average power between these
2 approaches differed by several orders of magnitude over many voxels.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Did I make some conceptual misunderstanding? Are the 2 approaches I used not equivalent? Or does source.avg.pow not contain the average power at all?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Any comments would be greatly appreciated!<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Best regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Son<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:7.5pt;font-family:"Times New Roman",serif;color:#888888;mso-fareast-language:DE">Son Ta Dinh, M.Sc.</span><span lang="EN-US" style="font-size:12.0pt;font-family:"Times New Roman",serif;color:#888888;mso-fareast-language:DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:7.5pt;font-family:"Times New Roman",serif;color:#888888;mso-fareast-language:DE">PhD student in Human Pain Research</span><span lang="EN-US" style="font-size:12.0pt;font-family:"Times New Roman",serif;color:#888888;mso-fareast-language:DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Times New Roman",serif;color:#888888;mso-fareast-language:DE">Klinikum rechts der Isar</span><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:#888888;mso-fareast-language:DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Times New Roman",serif;color:#888888;mso-fareast-language:DE">Technische Universität München<br>
Munich, Germany<br>
Phone: <a href="tel:%2B49%2089%204140%207664" target="_blank"><span style="color:blue">+49 89 4140 7664</span></a><br>
<a href="http://www.painlabmunich.de/" target="_blank"><span style="color:blue">http://www.painlabmunich.de/</span></a></span><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:#888888;mso-fareast-language:DE"><o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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