<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css" style="display:none;"><!-- P {margin-top:0;margin-bottom:0;} --></style>
</head>
<body dir="ltr">
<div id="divtagdefaultwrapper" style="font-size:12pt;color:#000000;font-family:Calibri,Helvetica,sans-serif;" dir="ltr">
<p style="margin-top:0;margin-bottom:0">Dear Vladimir,</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">For anyone interested, I used SPM to make a template head model which I'm going to use to do beamforming in FT.</p>
<p style="margin-top:0;margin-bottom:0">I have queries with regards to the source analysis pipeline I'm using in FT, as the results I get don't seem right.</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">Vladimir, following our previous email exchange (and thanks to your suggestions), I have now managed to compute the lead field matrix in FT (by removing eeglab and fieldtrip directories from the path, and adding spm's).</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">I want to contrast the sources of two groups of participants (high- vs. low-learners) in two frequency bands (low: 2.5-4.5 Hz; high: 12-32 Hz), from 0.20-1 sec post stimulus onset.</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">Here is my pipeline:</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">% Calculate the cross spectral density matrix (e.g., for the
<span style="font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;">
12-32 Hz </span>frequency band)</p>
<p style="margin-top:0;margin-bottom:0"></p>
<div>cfg = [];</div>
<div>cfg.method = 'mtmfft';</div>
<div>cfg.output = 'powandcsd';</div>
<div>cfg.foilim = [22 22];</div>
<div>cfg.taper = 'dpss';</div>
<div>cfg.tapsmofrq = 10;</div>
<div>cfg.keeptrials = 'yes';</div>
<div>cfg.keeptapers = 'no';</div>
<div>cfg.toi = 0.6;</div>
<div>cfg.t_ftimwin = 0.4;</div>
<div>freq = ft_freqanalysis(cfg, EEGft);</div>
<br>
<p></p>
<p style="margin-top:0;margin-bottom:0"></p>
<div>% Source analysis using DICS beamformer</div>
<div>cfg = [];</div>
<div>cfg.headmodel = vol1;</div>
<div>cfg.grad = sens1;</div>
<div>cfg.senstype = 'eeg';</div>
<div>cfg.grid = grid;</div>
<div>cfg.method = 'dics';</div>
<div>cfg.frequency = <span>[12 32]</span>;</div>
<div>cfg.latency = <span>[0.2 1];</span></div>
<div>cfg.dics.projectnoise = 'yes';</div>
<div>cfg.dics.lambda = 0;</div>
<div>cfg.dics.keepfilter = 'yes';</div>
<div>cfg.dics.realfilter = 'yes';</div>
<div>sourceA = ft_sourceanalysis(cfg, freq);</div>
<div><br>
</div>
<div>% Plot sources</div>
<div>cfg = [];</div>
<div>cfg.method = 'slice';</div>
<div>cfg.funparameter = 'pow';</div>
<div>ft_sourceplot(cfg, sourceA);</div>
<div><br>
</div>
=> The source plots look weird though - they scale from 0 to x10^45, and are totally black.
<p></p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">1) Am I doing something wrong in the freqanalysis or the sourceanalysis?</p>
<p style="margin-top:0;margin-bottom:0">2) Do I need to do the ft_sourceanalysis separately for each participant?</p>
<p style="margin-top:0;margin-bottom:0">3) Is there a way to average the results of the source analysis over groups of participants?</p>
<p style="margin-top:0;margin-bottom:0">4) Could you give any direction/resource on how to statistically compare the sources of different groups?</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">As you all know this is a very exciting but also not trivial analysis.. so I'd be extremely grateful for any help at this point, it'd be very much appreciated! <span style="font-size: 12pt;">Thanks so much in advance!</span></p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">Best,</p>
<p style="margin-top:0;margin-bottom:0">Ioanna</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
</div>
</body>
</html>