<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Dear David,<div><br></div><div>I won't discuss whether this is a sensible comment by the reviewer, but here are some basic steps that you could take.</div><div><br></div><div>To compute the circular correlation between two signals, you obviously need to obtain the phase angles first.</div><div>One option to do this is to use a Hilbert transform on band-pass filtered data (on a single-trial level)</div><div>As soon as you have your single trial phase angles, you can compute the correlation between two signals within each subject.</div><div>Once you have done this, you could see whether there is a consistent pattern over subjects.</div><div><br></div><div>You can find similar approaches in the following papers:</div><div><br></div><div><span class="Apple-style-span" style="font-size: 12px; ">van Elswijk, G., Maij, F., Schoffelen, J.-M., Overeem, S., Stegeman, D. F., & Fries, P. (2010). Corticospinal Beta-Band Synchronization Entails Rhythmic Gain Modulation. Journal of Neuroscience, 30(12), 4481–4488. <a href="http://doi.org/10.1523/JNEUROSCI.2794-09.2010">http://doi.org/10.1523/JNEUROSCI.2794-09.2010</a></span></div><div><span class="Apple-style-span" style="font-size: 12px; "><br></span></div><div><span class="Apple-style-span" style="font-size: 12px; "><span class="Apple-style-span" style="font-size: medium; ">Keil, J., Timm, J., SanMiguel, I., Schulz, H., Obleser, J., & Schonwiesner, M. (2014). Cortical brain states and corticospinal synchronization influence TMS-evoked motor potentials. Journal of Neurophysiology, 111(3), 513–519. <a href="http://doi.org/10.1152/jn.00387.2013">http://doi.org/10.1152/jn.00387.2013</a></span></span></div><div><span class="Apple-style-span" style="font-size: 12px; "><span class="Apple-style-span" style="font-size: medium; "><br></span></span></div><div><span class="Apple-style-span" style="font-size: 12px; "><span class="Apple-style-span" style="font-size: medium; ">Good luck,</span></span></div><div><span class="Apple-style-span" style="font-size: 12px; "><span class="Apple-style-span" style="font-size: medium; "><br></span></span></div><div><span class="Apple-style-span" style="font-size: 12px; "><span class="Apple-style-span" style="font-size: medium; ">Julian</span></span></div><div><br><div><div>Am 02.02.2016 um 09:14 schrieb David Syloni:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div dir="ltr">Dear Julian,<div><br></div><div>Thank you for the answer. I was asked by reviewers to calculate circular correlation instead of PLV. Sorry for too general description.</div><div>Actually, I found the toolbox , but I don't understand how to compute " sample of angles in radians" (the input for the <span style="color:rgb(0,0,0)">circ_corrcc function</span> ). </div><div>I would very appreciate a help to transform my fieldtrip data to the input format , required by <span style="color:rgb(0,0,0)">circ_corrcc.</span></div><div><span style="color:rgb(0,0,0)"><br></span></div><div><span style="color:rgb(0,0,0)">Thanks!</span></div><div><span style="color:rgb(0,0,0)"><br></span></div><div><span style="color:rgb(0,0,0)"><br></span></div><div><span style="color:rgb(0,0,0)">David</span></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Feb 2, 2016 at 9:57 AM, Julian Keil <span dir="ltr"><<a href="mailto:julian.keil@gmail.com" target="_blank">julian.keil@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi David,<br>
<br>
to compute circular statistics (e.g. phase correlations) you need to leave fieldtrip a bit.<br>
Here's the toolbox I usually use: <a href="http://www.mathworks.com/matlabcentral/fileexchange/10676-circular-statistics-toolbox--directional-statistics-" rel="noreferrer" target="_blank">http://www.mathworks.com/matlabcentral/fileexchange/10676-circular-statistics-toolbox--directional-statistics-</a><br>
<br>
As you don't describe why you need circular statistics, it's a bit hard to give a more helpful answer.<br>
<br>
Good luck,<br>
<br>
Julian<br>
<div><div class="h5"><br>
Am 01.02.2016 um 13:40 schrieb David Syloni:<br>
<br>
> Dear Fieldtripers,<br>
><br>
> I'm trying to apply connectivity analysis with continuous EEG data.<br>
><br>
> I'm using:<br>
><br>
><br>
><br>
> cfg = [];<br>
> cfg.method = 'mtmfft';<br>
> cfg.taper = 'dpss';<br>
> cfg.output = 'fourier';<br>
> cfg.tapsmofrq = 4;<br>
> cfg.width=2;<br>
> cfg.foilim = [0 250];<br>
> cfg.keeptrials = 'yes';<br>
> freq = ft_freqanalysis(cfg, data_no_artifacts);<br>
><br>
><br>
><br>
><br>
> cfg = [];<br>
> cfg.method = 'plv';<br>
> 'mtmfft'<br>
> cfg.foilim = [8 12];<br>
> cfg.bandwidth=5;<br>
> cfg.tapsmofrq = 4;<br>
> cfg.keeptrials = 'yes';<br>
> cfg.output = 'powandcsd';<br>
> cfg.channelcmb = c;<br>
> coh = ft_connectivityanalysis(cfg, freq);<br>
><br>
> Right now I should calculate Circular Correlation and I'm stuck with it.<br>
><br>
> I would very appreciate your help!<br>
><br>
> Thanks in advance,<br>
><br>
> David<br>
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