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<div>Hi everyone,<br>
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<div>I am a total beginner in FT and have been trying to run a cluster-based permutation test (between-subjects) on time-frequency data exported from BESA Connectivity. I used the function besa2fieldtrip on .tfc data, which according to this tutorial <a href="https://www.fieldtriptoolbox.org/getting_started/besa/#reading-in-data-files-from-besa" title="https://www.fieldtriptoolbox.org/getting_started/besa/#reading-in-data-files-from-besa
Ctrl+Click or tap to follow the link">https://www.fieldtriptoolbox.org/getting_started/besa/#reading-in-data-files-from-besa</a>
should produce output similar to ft_freqanalysis. I did have to do some tweaking to get the 2 power spectra to be 4-D matrices with the following dimord: subj_chan_freq_time. I defined my configuration using this tutorial <a href="https://www.fieldtriptoolbox.org/tutorial/cluster_permutation_freq/#permutation-test">https://www.fieldtriptoolbox.org/tutorial/cluster_permutation_freq/#permutation-test</a>,
leaving almost all the settings as-is.<br>
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<div>When I run ft_freqstatistics, I get the following readout:<br>
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<div>Error using findcluster (line 66)</div>
<div>invalid dimension of spatdimneighbstructmat</div>
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<div>Error in clusterstat (line 214)</div>
<div> posclusobs = findcluster(tmp, connmat, cfg.minnbchan);</div>
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<div>Error in ft_statistics_montecarlo (line 363)</div>
<div> [stat, cfg] = clusterstat(cfg, statrand, statobs);</div>
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<div>Error in ft_freqstatistics (line 193)</div>
<div> [stat, cfg] = statmethod(cfg, dat, design);<br>
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<div>I turned on debugging, and the error happens on this line:<br>
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<div>if ~ismatrix(spatdimneighbstructmat) || ~all(size(spatdimneighbstructmat)==spatdimlength)</div>
<div> ft_error('invalid dimension of spatdimneighbstructmat');</div>
<div>end<br>
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<div><br>
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<div>It seems that findcluster wants the size of my <span style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);">s</span><span style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);">pa</span><span style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);">tdimneighbstructmat
to be 1 (size assigned to spatdimlength earlier in the function), but it is a 129*129 matrix (EGI 129 channel net). I find this odd, since the function documentation states:<br>
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<div>"The neighbourhood structure for the first dimension is specified using <span style="font-size: 12pt;">s</span><span style="font-size: 12pt;">p</span><span style="font-size: 12pt;">atdimneighbstructmat, which is a 2D (N1xN1) matrix. Each row and each column</span><span style="font-size: 12pt;"> corresponds
to a channel (combination) along the first dimension and along that </span><span style="font-size: 12pt;">row/column, elements with "1" define the neighbouring channel(s) (combinations)."</span></div>
<div><span style="font-size: 12pt;"><br>
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<div><span style="font-size: 12pt;">From that description, it seems that my spatdimneighbstructmat is correct, so I have trouble interpreting this error or figuring out what I should change.</span></div>
<div><span style="font-size: 12pt;"><br>
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<div><span style="font-size: 12pt;">All that said, I will say that I am still unsure what the "data" parameter in ft_prepare_neighbours should be. At the moment, I am putting the channel configuration in there, but this may be wrong. </span></div>
<span style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);"> </span><br>
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<p>Does anyone have experience with BESA data and/or defining neighbour structure for EGI nets, and wouldn't mind having a look at my data/configuration? Thank you very much in advance!<br>
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<p>All the best,<br>
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<p>Valentina<br>
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<font color="#808080"><font size="2">Valentina Jelinčić, M.Sc.</font> </font>
<div><font size="2" color="#808080">PhD student | Research Group Health Psychology | KU Leuven</font></div>
<div><font size="2" color="#808080">Tiensestraat 102, room 02.86</font></div>
<div><font size="2" color="#808080">3000 Leuven, Belgium</font></div>
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