Hi Jason,<br/>
<br/>
when everything is done and you just use ft_sourcegrandaverag to create a decent input structure for statistics (which can be done in other ways as well), replace the original pos fields (that correspond with the 'crooked' grids in the individual subjects) with the pos from the MNI template head. After that all plotting/statistics is done in MIN space, you basically trasnform your subjects to MIN that way.<br/>
<br/>
Michael<br>
<br>
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<b>Gesendet:</b> Freitag, 16. März 2012 um 15:17 Uhr<br/>
<b>Von:</b> "Jason Chan" <chan@med.uni-frankfurt.de><br/>
<b>An:</b> "'Email discussion list for the FieldTrip project'" <fieldtrip@donders.ru.nl><br/>
<b>Betreff:</b> Re: [FieldTrip] missing pos in beamforming
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--><div><div class="WordSection1"><p class="MsoNormal"><span style="font-size: 11.0pt;font-family: Calibri , sans-serif;color: rgb(31,73,125);">Hi Michael,</span></p><p class="MsoNormal"><span style="font-size: 11.0pt;font-family: Calibri , sans-serif;color: rgb(31,73,125);"> </span></p><p class="MsoNormal"><span style="font-size: 11.0pt;font-family: Calibri , sans-serif;color: rgb(31,73,125);">Many thanks for your informative reply. I was able to use the reverse normalization technique and eliminated the ft_sourceinterpolate and ft_volumenormalise commands.</span><span style="font-family: "Courier New";"></span></p><p class="MsoNormal"><span style="font-size: 11.0pt;font-family: Calibri , sans-serif;color: rgb(31,73,125);"> However, after I subtract ‘sourceA’ from ‘sourceB’ I now get the error “different grid locations in source reconstructions” when I try to do a ft_sourcegrandaverage. Any suggestions would be very welcome.</span></p><p class="MsoNormal"><span style="font-size: 11.0pt;font-family: Calibri , sans-serif;color: rgb(31,73,125);"> </span></p><p class="MsoNormal"><span style="font-size: 11.0pt;font-family: Calibri , sans-serif;color: rgb(31,73,125);">Thanks in advance.</span></p><p class="MsoNormal"><span style="font-size: 11.0pt;font-family: Calibri , sans-serif;color: rgb(31,73,125);">Jason</span></p><p class="MsoNormal"><span style="font-size: 11.0pt;font-family: Calibri , sans-serif;color: rgb(31,73,125);"> </span></p><p class="MsoNormal"><b><span style="font-size: 10.0pt;font-family: Tahoma , sans-serif;">From:</span></b><span style="font-size: 10.0pt;font-family: Tahoma , sans-serif;"> fieldtrip-bounces@donders.ru.nl [mailto:fieldtrip-bounces@donders.ru.nl] <b>On Behalf Of </b>Michael Wibral<br/><b>Sent:</b> Mittwoch, 14. März 2012 20:29<br/><b>To:</b> Email discussion list for the FieldTrip project<br/><b>Subject:</b> Re: [FieldTrip] missing pos in beamforming</span></p><p class="MsoNormal"> </p><p class="MsoNormal" style="margin-bottom: 12.0pt;">Dear Jason,<br/><br/>the pos indicates where the original sources were (i.e. on a regular grid with a certain spacing or self-defined). After interpolation this information does not reflect the data anymore. I would suggest to use Ingrid nieuwenhuis famous reverse normalization technique to create individual subject grids taht all match in MNI space - the script is found on the ft website. Sourceinterpoltae should really only be used for plotting IMHO.<br/><br/>Michael</p><div style="border: none;border-left: solid rgb(195,217,229) 1.5pt;padding: 0.0cm 0.0cm 0.0cm 8.0pt;margin-left: 7.5pt;margin-top: 7.5pt;margin-right: 3.75pt;margin-bottom: 3.75pt;"><div style="margin-bottom: 7.5pt;"><p class="MsoNormal"><b>Gesendet:</b> Mittwoch, 14. März 2012 um 17:28 Uhr<br/><b>Von:</b> "Jason Chan" <<a href="chan@med.uni-frankfurt.de" target="_blank">chan@med.uni-frankfurt.de</a>><br/><b>An:</b> <a href="fieldtrip@donders.ru.nl" target="_blank">fieldtrip@donders.ru.nl</a><br/><b>Betreff:</b> [FieldTrip] missing pos in beamforming </p></div><div><div><div><p class="MsoNormal">Greetings,</p><p class="MsoNormal">I am adapting the beamformer tutorial to my data. When I <span style="font-size: 10.0pt;font-family: "Courier New";color: black;">sourceinterpolate</span> the subtracted sourceA from sourceB data, the ‘pos’ disappears. This seems to be important for the volume normalization and Grand Average. I am running Fieldtrip version: 20110917. I have placed the code below.</p><p class="MsoNormal"> </p><p class="MsoNormal">Many thanks in advance.</p><p class="MsoNormal">Jason</p><p class="MsoNormal"> </p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: black;"> </span></p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: black;">Young_CombineFilter_sourceDiff_16_3={};</span></p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: blue;">for</span><span style="font-size: 10.0pt;font-family: "Courier New";color: black;"> i=1:length(Young_CombineFilter_beamform_16_3);</span></p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: black;"> cfg=[];</span></p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: black;"> Young_CombineFilter_sourceDiff_16_3{i} =Young_CombineFilter_beamform_16_3{i}.sourceA;</span></p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: black;"> Young_CombineFilter_sourceDiff_16_3{i}.avg.pow =(Young_CombineFilter_beamform_16_3{i}.sourceA.avg.pow - Young_CombineFilter_beamform_16_3{i}.sourceB.avg.pow)./Young_CombineFilter_beamform_16_3{i}.sourceB.avg.pow;</span></p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: black;"> </span></p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: black;"> cfg = [];</span></p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: black;"> cfg.downsample = 2;</span></p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: black;"> cfg.parameter = </span><span style="font-size: 10.0pt;font-family: "Courier New";color: rgb(160,32,240);">'avg.pow'</span><span style="font-size: 10.0pt;font-family: "Courier New";color: black;">;</span></p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: black;"> cfg.anatomy = mri{i};</span></p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: black;"> cfg.keepfilter=</span><span style="font-size: 10.0pt;font-family: "Courier New";color: rgb(160,32,240);">'yes'</span><span style="font-size: 10.0pt;font-family: "Courier New";color: black;">;</span></p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: black;"> cfg.interpmethod=</span><span style="font-size: 10.0pt;font-family: "Courier New";color: rgb(160,32,240);">'linear'</span><span style="font-size: 10.0pt;font-family: "Courier New";color: black;">;</span></p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: black;"> Young_CombineFilter_sourceDiffInt_16_3{i}=ft_sourceinterpolate(cfg,Young_CombineFilter_sourceDiff_16_3{i}, mri_young{i});</span></p><p class="MsoNormal"><span style="font-size: 10.0pt;font-family: "Courier New";color: blue;">end</span><span style="font-size: 10.0pt;font-family: "Courier New";color: black;">;</span></p></div></div></div></div><p class="MsoNormal"> </p></div></div>
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