<div dir="ltr">Dear Luca,<div><br></div><div>You seem to be trying to use ft_selectdata for averaging over repetitions (i.e. trials/epochs), but are providing data-structures of <i>patients</i>. </div><div>Easy mistake, and probably because in the tutorials you were looking at within-subject statistics was explained.</div><div><br></div><div>To average across subjects use ft_timelockgrandaverage or ft_freqgrandaverage. You should be able to proceed in a similar fashion.</div><div>To average/select data within a single datastructure, use ft_selectdata.<br></div><div><br></div><div>hope this helps,</div><div>Stephen</div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Op di 13 aug. 2019 om 12:20 schreef Luca Moretti <<a href="mailto:luca-moretti@hotmail.it">luca-moretti@hotmail.it</a>>:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<div class="gmail-m_6873866538088984175WordSection1">
<p class="MsoNormal">Dear all,</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I am having some problems with plotting the results of a cluster based permutation test.
</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I am running a within subjects’ experiment with 8 conditions combined in a 2X2X2 design. Theta and Alpha power are used as dependent variables. I would like to test some main effects and interactions, but first of all I have tried to compare
two conditions ignoring the others (just as a practice before combining the conditions for a more theoreticaly relevant comparison).</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">To this aim, I have created a cell array in which I have stored the normalized frequency power for each of the 20 participants. In this way I get a cell array with 8 conditions, each containing 20 cells (one per participant).
</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Here is what I did:</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">cfg = [];</p>
<p class="MsoNormal">cfg.layout=layout;</p>
<p class="MsoNormal">cfg.method = 'template';</p>
<p class="MsoNormal">cfg.template = 'C:\Fieldtrip\template\neighbours\easycapM1_neighb.mat';</p>
<p class="MsoNormal">cfg.feedback = 'yes';</p>
<p class="MsoNormal">cfg.elecfile = 'C:\Fieldtrip\template\electrode\easycap-M1.txt';</p>
<p class="MsoNormal">neighbours = ft_prepare_neighbours(cfg);</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">subj = 20;</p>
<p class="MsoNormal">design = zeros(2,2*subj);</p>
<p class="MsoNormal">for i = 1:subj</p>
<p class="MsoNormal">design(1,i) = i;</p>
<p class="MsoNormal">end</p>
<p class="MsoNormal">for i = 1:subj</p>
<p class="MsoNormal">design(1,subj+i) = i;</p>
<p class="MsoNormal">end</p>
<p class="MsoNormal">design(2,1:subj) = 1;</p>
<p class="MsoNormal">design(2,subj+1:2*subj) = 2;</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">cfg = [];</p>
<p class="MsoNormal">cfg.channel = {'all'};</p>
<p class="MsoNormal">cfg.frequency = [4 12];</p>
<p class="MsoNormal">cfg.latency = [0 1.5];</p>
<p class="MsoNormal">cfg.method = 'montecarlo';</p>
<p class="MsoNormal">cfg.statistic = 'depsamplesT';</p>
<p class="MsoNormal">cfg.correctm = 'cluster';</p>
<p class="MsoNormal">cfg.clusteralpha = 0.05;</p>
<p class="MsoNormal">cfg.clusterstatistic = 'maxsum';</p>
<p class="MsoNormal">cfg.minnbchan = 2;</p>
<p class="MsoNormal">cfg.tail = 0;</p>
<p class="MsoNormal">cfg.clustertail = 0;</p>
<p class="MsoNormal">cfg.alpha = 0.05;</p>
<p class="MsoNormal">cfg.numrandomization = 500;</p>
<p class="MsoNormal">cfg.design = design;</p>
<p class="MsoNormal">cfg.ivar = 2;</p>
<p class="MsoNormal">cfg.uvar = 1;</p>
<p class="MsoNormal">cfg.neighbours = neighbours;</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">stat1 = ft_freqstatistics(cfg, normalized{1,1}{:}, normalized{1,2}{:});</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">So far so good. Following the online tutorial I have tried to execute the following code:</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">sigposmask = (stat1.posclusterslabelmat==1) & stat1.mask;</p>
<p class="MsoNormal">signegmask = (stat1.negclusterslabelmat==1) & stat1.mask;</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">cfg = [];</p>
<p class="MsoNormal">cfg.frequency = [4 12];</p>
<p class="MsoNormal">cfg.avgoverrpt = 'yes';</p>
<p class="MsoNormal">cfg.parameter = {'powspctrm','powspctrm_b'};</p>
<p class="MsoNormal">WDW_avg = ft_selectdata(cfg, normalized{1,1}{:});</p>
<p class="MsoNormal">CDW_avg = ft_selectdata(cfg, normalized{1,2}{:});</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">WDW_avg.mask = signegmask;</p>
<p class="MsoNormal">CDW_avg.mask = signegmask;</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">cfg = [];</p>
<p class="MsoNormal">cfg.elec = elec;</p>
<p class="MsoNormal">cfg.colorbar = 'no';</p>
<p class="MsoNormal">cfg.maskparameter = 'mask'; % use the thresholded probability to mask the data</p>
<p class="MsoNormal">cfg.maskstyle = 'box';</p>
<p class="MsoNormal">cfg.parameter = 'powspctrm_b';</p>
<p class="MsoNormal">cfg.maskfacealpha = 0.5;</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">figure; ft_multiplotER(cfg, WDW_avg, CDW_avg);</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">However, when I try to run the line:</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">WDW_avg = ft_selectdata(cfg, normalized{1,1}{:});<u></u><u></u></p>
<p class="MsoNormal">there are no repetitions, so averaging is not possible</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I have therefore tried to remove the {:}, but still:</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">WDW_avg = ft_selectdata(cfg, normalized{1,1};<u></u><u></u></p>
<p class="MsoNormal">Invalid input argument of type 'cell'. Input must be a structure or a Java or COM object</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I do understand the errors, but I don’t see how the data should have been stored if not in a cell array. Can someone help?</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Thank you in advance,</p>
<p class="MsoNormal">Luca</p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Inviato da <a href="https://go.microsoft.com/fwlink/?LinkId=550986" target="_blank">
Posta</a> per Windows 10</p>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
</div>
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</blockquote></div>