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</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#16355A'>Dear fellow EEGLab users,<o:p></o:p></span></p><p class=MsoNormal><span style='color:#16355A'>Having used EEGLab for a while now to compute inter-channel (phase, etc) coherence, I recently stumbled upon the following article: <a href="http://brainimaging.waisman.wisc.edu/~lutz/Lachaux_et_all_IJBChaos_2000.pdf">http://brainimaging.waisman.wisc.edu/~lutz/Lachaux_et_all_IJBChaos_2000.pdf</a> (“studying single-trials of phase synchronous activity in the brain”, Lachaux et al., International Journal of Bifurcation and Chaos (!), vol. 10, 2000) where the authors are describing a method for studying phase locking in single trials. As far as I understand, if we do such a thing in EEGLab, we would just get a coherence value of 1, by definition. So, I was wondering whether someone could help me along the way of getting this to run in EEGLab, (I’m okay with matlab scripts, just not with hardcore math). <o:p></o:p></span></p><p class=MsoNormal><span style='color:#16355A'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#16355A'>Recently, although I cannot find the specific email anymore, someone else had a similar enquiry. Something quite possible, even easy, to do in EEGLab would be to hack an epoch to ‘sub-epoch’ pieces – say, turn my single 5 second epoch into 200 overlapping ones, with each being 200 ms (so they’d overlap quite a lot), run newcrossf over that, et voila. Yet, this does not seem like the ultimate answer, since it is, quite possible that channels should first synchronise for a few hundred milliseconds at one angle, then ‘scatter’, and a few hundred milliseconds later, <i>resynchronise</i> over another, possibly even opposite angle. It seems to me like Lachaux et al. here suggest something to cope with it – that is, we could use, for instance, 4 wavelet cycles across time to extract angles, and then use an ‘integration window’ of 8 cycles (see figure p.2432) to compare 8 angles and see whether they point in the same direction.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#16355A'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#16355A'>So, my proposed way of doing this in EEGLab would be to, for example, re-epoch my 5 seconds in 5 consecutive 1 second epochs, then hack each 1 second epoch in 8 200 ms epochs (a bit overlapping), and thus compute, 5 times, the ITC over this. Does this sound sane to you?<o:p></o:p></span></p><p class=MsoNormal><span style='color:#16355A'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#16355A'>Best,<o:p></o:p></span></p><p class=MsoNormal><span style='color:#16355A'>Mich<i><o:p></o:p></i></span></p><p class=MsoNormal><span style='color:#16355A'><o:p> </o:p></span></p><p class=MsoNormal><i><span style='font-size:10.0pt;color:#16355A'>Michiel Spapé<o:p></o:p></span></i></p><p class=MsoNormal><i><span style='font-size:10.0pt;color:#16355A'>Research Fellow<o:p></o:p></span></i></p><p class=MsoNormal><i><span style='font-size:10.0pt;color:#16355A'>Perception & Action group<o:p></o:p></span></i></p><p class=MsoNormal><i><span style='font-size:10.0pt;color:#16355A'>University of Nottingham<o:p></o:p></span></i></p><p class=MsoNormal><i><span style='font-size:10.0pt;color:#16355A'>School of Psychology<o:p></o:p></span></i></p><p class=MsoNormal><i><span style='font-size:10.0pt;color:#16355A'>www.cognitology.eu</span></i><i><span style='font-size:10.0pt;color:#16355A'><o:p></o:p></span></i></p><p class=MsoNormal><o:p> </o:p></p></div><br/>
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