<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi Stephan et al,<div><br></div><div>Any balancing coefficients (e.g. the digital weights for the bti-system, or ctf's 3d order gradient coefficients) are only applied to the leadfield if they end up in the data.grad.tra matrix. These .tra matrices will be compiled when reading the data header, by functions like XXX2grad (in fileio/private: ctf2grad, bti2grad, fif2grad). </div><div>You can check whether it is constructed using hdr.orig.projs. </div><div>If not, it may be worthwile to implement I guess.</div><div><br></div><div>Best,</div><div><br></div><div>JM</div><div><br></div><div><br></div><div><br><div><div>On Jun 3, 2011, at 11:00 AM, Stephan Moratti wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi Michael y Elena,<div><br></div><div>I am following your discussion with great interest as I have just started to work with Neuromag data. As FT uses the MNE toolbox to read the data I assume that the SSP vectors are applied to the data during reading the data. However, the SSP vectors are stored in "data.hdr.orig.projs". However, when I go on with averaging in the ERF from timelockanalysis I cannot find this info. So my question is, does FT apply the SSP vectors later on also to the leadfield when calculating it? I assume that not, as the SSP vectors are not passed on further. How can I apply the SSP vectors to the leadfield to get correct results?</div><div><br></div><div>Best and thanks,</div><div><br></div><div>STephan</div><div><br><div><div>El 02/06/2011, a las 19:20, Michael Wibral escribió:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div bgcolor="#FFFFFF" style="font-size:12px;background-color:#FFFFFF;font-family:Verdana, Arial, sans-serif;">Hi Elena,<br><br>I assume that you were well aware of the difficulties in beamforming evoked activty and baseline normalisation and these things, your results really look that way. I mus say I am quite puzzled by the results - could it be a color scaling problem in the plot? I think this mmay be a problem because most of your plot is a peak power, only a tiny corner seems to be in a low-amplitude range.<br><br>What you could do as a workaround is to average the separate results with a weighting per voxel and that is corresponding to the squared norms of the leadfields for the respective modalities for a given voxel , this would guarantee equal amounts of backprojected noise from both modalities (if I'm not mistaken).<br><br>Michael<br>PS: I am away for a couple of days, but after that, I'll be happy to resume this discussion.<br><br><br><blockquote style="border-left: 2px solid blue; margin-left: 5px; padding-left: 5px; padding-top: 5px;"><hr><b>Von:</b> "Elena Orekhova" <<a href="mailto:Elena.Orekhova@neuro.gu.se">Elena.Orekhova@neuro.gu.se</a>><br><b>Gesendet:</b> Jun 2, 2011 6:22:03 PM<br><b>An:</b> "Email discussion list for the FieldTrip project" <<a href="mailto:fieldtrip@donders.ru.nl">fieldtrip@donders.ru.nl</a>><br><b>Betreff:</b> Re: [FieldTrip] combining magnetometers and planad gradiometers for analysis<br><br><div style="font-size: 12px; background-color: rgb(255, 255, 255); font-family: Verdana,Arial,sans-serif;"><div style="direction: ltr; font-family: Tahoma; color: rgb(0, 0, 0); font-size: 10pt;">@font-face { font-family: "\FF2D \FF33 \660E \671D "; }@font-face { font-family: "Cambria Math"; }@font-face { font-family: "Calibri"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: Cambria; }.MsoChpDefault { font-family: Cambria; }div.WordSection1 { page: WordSection1; }<p class="MsoNormal"><span style="font-family: Calibri;">Dear </span><span style="font-family: Calibri; background: none repeat scroll 0% 0% white;">Michael, </span></p><div><span style="font-family: Calibri; background: none repeat scroll 0% 0% white;"> </span><br class="webkit-block-placeholder"></div><p class="MsoNormal"><span style="font-family: Calibri; background: none repeat scroll 0% 0% white;">I have tried to multiply the leadfield by -1 as you suggested:</span></p><div><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125); background: none repeat scroll 0% 0% white;"> </span><br class="webkit-block-placeholder"></div><p class="MsoNormal" style=""><span style="font-size: 10pt; font-family: Courier; color: blue;">for</span><span style="font-size: 10pt; font-family: Courier; color: black;"> i = 1 : size (grid.leadfield, 2)</span></p><p class="MsoNormal" style=""><span style="font-size: 10pt; font-family: Courier;"><span style=""> </span>grid.leadfield{i}(3:3:306, :) = -1*grid.leadfield{i}(3:3:306, :);</span></p><p class="MsoNormal" style=""><span style="font-size: 10pt; font-family: Courier; color: blue;">end</span></p><div style=""><span style="font-family: Calibri;"> </span><br class="webkit-block-placeholder"></div><p class="MsoNormal" style=""><span style="font-family: Calibri;">This had no effect on the </span><span style="font-family: Calibri; color: rgb(160, 32, 240);">'lcmv'</span><span style="font-family: Calibri;"> output. I attached the pictures for ‘GRA only, ’MAG only’ and ‘GRA + MAG’</span></p><div><span style="font-family: Calibri;"> </span><br class="webkit-block-placeholder"></div><p class="MsoNormal"><span style="font-family: Calibri;">In this experiment I measured evoked field in response to <span style=""> </span>the unilateral (left) click. </span></p><p class="MsoNormal"><span style="font-family: Calibri;">The source is expected to be in the right superior temporal cortex. <span style=""> </span>This is the case <span style=""> </span>for </span><span style="font-family: Calibri;"><span style=""> </span>‘GRA only' and ’MAG only’ datasets. The combined sensors give meaningless result.</span></p><div><span style="font-family: Calibri;"> </span><br class="webkit-block-placeholder"></div><p class="MsoNormal"><span style="font-family: Calibri;">Elena</span></p><div> </div><div style="font-family: Times New Roman; color: rgb(0, 0, 0); font-size: 16px;"><hr><div id="divRpF409531" style="direction: ltr;"><font color="#000000" face="Tahoma" size="2"><b>From:</b> <a href="mailto:fieldtrip-bounces@donders.ru.nl">fieldtrip-bounces@donders.ru.nl</a> [<a href="mailto:fieldtrip-bounces@donders.ru.nl">fieldtrip-bounces@donders.ru.nl</a>] on behalf of Michael Wibral [<a href="mailto:michael.wibral@web.de">michael.wibral@web.de</a>]<br><b>Sent:</b> Wednesday, June 01, 2011 4:04 PM<br><b>To:</b> Email discussion list for the FieldTrip project<br><b>Subject:</b> Re: [FieldTrip] combining magnetometers and planad gradiometers for analysis</font><br> </div><div> </div><div>Dear Elena,<br><br>could you give the following a try: invert (*-1) the leadfileds for one of the two sensor types. Let me know what happens.<br>I would also be interested in taking a look at the results - maybe you could sent images off-list: Michael.Wibral <at> <a href="http://web.de">web.de</a>.<br><br>Michael<br><br><br><br><blockquote style="border-left: 2px solid blue; margin-left: 5px; padding-left: 5px; padding-top: 5px;"><hr><b>Von:</b> "Elena Orekhova" <<a href="mailto:Elena.Orekhova@neuro.gu.se">Elena.Orekhova@neuro.gu.se</a>><br><b>Gesendet:</b> Jun 1, 2011 12:23:29 PM<br><b>An:</b> "<a href="mailto:fieldtrip@donders.ru.nl">fieldtrip@donders.ru.nl</a>" <<a href="mailto:fieldtrip@donders.ru.nl">fieldtrip@donders.ru.nl</a>><br><b>Betreff:</b> [FieldTrip] combining magnetometers and planad gradiometers for analysis<br><br><div><div style="direction: ltr; font-family: Tahoma; color: rgb(0, 0, 0); font-size: 10pt;">@font-face { font-family: "Arial"; }@font-face { font-family: "Times"; }@font-face { font-family: "\FF2D \FF33 \660E \671D "; }@font-face { font-family: "Cambria Math"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: Cambria; }p { margin-right: 0cm; margin-left: 0cm; font-size: 10pt; font-family: Times; }.MsoChpDefault { font-family: Cambria; }div.WordSection1 { page: WordSection1; }<p><span style="font-size: 12pt; font-family: Arial;">Dear fieldtrippers, </span></p><p class="MsoNormal" style=""><span style="font-family: Arial;">This message is mainly for Neuromag users. </span></p><div style=""><span style="font-family: Arial;"> </span><br class="webkit-block-placeholder"></div><p class="MsoNormal" style=""><span style="font-family: Arial;">When I do<span style=""> </span>'lcmv' beamforming analysis separately on planar gradiometers or magnetometers, I get quite meaningful results.</span></p><p class="MsoNormal" style=""><span style="font-family: Arial;">If I combine the two types of sensors without weighting, the result is meaningless.</span></p><p class="MsoNormal" style=""><span style="font-family: Arial;">Apparently, the algorithm does not take care of different scales and units of the GRA and MAG measurements.<span style=""> </span>Does anybody know how to deal with this problem?</span></p><div style=""><span style="font-family: Arial;"> </span><br class="webkit-block-placeholder"></div><div style=""><span style="font-family: Arial;"> </span><br class="webkit-block-placeholder"></div><p class="MsoNormal" style=""><span style="font-family: Arial;">Elena</span></p><div><span style="font-size: 12pt; font-family: Arial;"> </span><br class="webkit-block-placeholder"></div><div> </div></div></div></blockquote></div></div></div></div></blockquote></div> _______________________________________________<br>fieldtrip mailing list<br><a href="mailto:fieldtrip@donders.ru.nl">fieldtrip@donders.ru.nl</a><br><a href="http://mailman.science.ru.nl/mailman/listinfo/fieldtrip">http://mailman.science.ru.nl/mailman/listinfo/fieldtrip</a></blockquote></div><br><div> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div><br class="Apple-interchange-newline">________________________________________________________</div><div>Stephan Moratti, PhD<br><br></div><div>see also: <a href="http://web.me.com/smoratti/">http://web.me.com/smoratti/</a><br><br></div><div>Universidad Complutense de Madrid</div><div>Facultad de Psicología</div><div>Departamento de Psicología Básica I</div><div>Campus de Somosaguas</div><div>28223 Pozuelo de Alarcón (Madrid)</div><div>Spain</div><div><br></div><div>and</div><div><br></div><div>Center for Biomedical Technology</div><div>Laboratory for Cognitive and Computational Neuroscience</div><div>Parque Científico y Tecnológico de la Universidad Politecnica de Madrid<br>Campus Montegancedo</div><div>28223 Pozuelo de Alarcón (Madrid)</div><div>Spain<br><br><br>email: <a href="mailto:smoratti@psi.ucm.es">smoratti@psi.ucm.es</a><br>Tel.: +34 679219982<br><br></div></span></div></span></div></span></div></span></div></span></span> </div> <br></div></div>_______________________________________________<br>fieldtrip mailing list<br><a href="mailto:fieldtrip@donders.ru.nl">fieldtrip@donders.ru.nl</a><br><a href="http://mailman.science.ru.nl/mailman/listinfo/fieldtrip">http://mailman.science.ru.nl/mailman/listinfo/fieldtrip</a></blockquote></div><br><div apple-content-edited="true"> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Dr. J.M. (Jan-Mathijs) Schoffelen </div><div>Donders Institute for Brain, Cognition and Behaviour, <br>Centre for Cognitive Neuroimaging,<br>Radboud University Nijmegen, The Netherlands</div><div><a href="mailto:J.Schoffelen@donders.ru.nl">J.Schoffelen@donders.ru.nl</a></div><div>Telephone: 0031-24-3614793</div></div></span></div></span> </div><br></div></body></html>