<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">
Hi Elisa,
<div class=""><br class="">
</div>
<div class="">Thanks for the additional information.</div>
<div class=""><br class="">
</div>
<div class="">
<div>
<blockquote type="cite" class="">
<div class="">
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<br class="">
</div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;" class="">In response to your reply:</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 11pt;" class=""><br class="">
</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-variant-ligatures: normal; font-variant-east-asian: normal; font-variant-position: normal; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 11pt;" class=""><i class="">Last but not least, is there a physiological or computational explanation for the impossibility of computing PAC on different electrodes?</i></span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-variant-ligatures: normal; font-variant-east-asian: normal; font-variant-position: normal; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 11pt;" class=""><i class=""><br class="">
I don’t understand the question underlying this question: given some data, and a function, one could most of the time produce a result. In that sense it is always possible. Whether or not that result is interpretable, that’s a different question, but it probably
does not depend on whether it was computed on electrode O1, or on electrode P6</i><br class="">
</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<br class="">
</div>
<div class="p2" style="caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; margin: 0px; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;" class="">The code of ft_crossfrequencyanalysis states that computation for different channels is not supported: </span></div>
<div class="p2" style="caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; margin: 0px; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;">
<br class="">
</div>
<div class="p2" style="caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; margin: 0px; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;" class="">Lines 85-86:</span><span style="font-size: 12pt;" class=""><span class="Apple-converted-space"> </span></span><br class="">
</div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<br class="">
</div>
<p class="p2" style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;">
</p>
<div style="margin: 0px; font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; color: rgb(2, 128, 9);" class="">
<span style="font-size: 12pt;" class="">% prior to 19 Jan 2017 this function had input options cfg.chanlow and cfg.chanhigh,</span></div>
<div style="margin: 0px; font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; color: rgb(2, 128, 9);" class="">
<span style="font-size: 12pt;" class="">% but nevertheless did not support between-channel CFC computations</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; min-height: 14px;" class="">
<br class="">
</div>
<div class="p2" style="caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; margin: 0px; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt; background-color: rgb(255, 255, 255); display: inline !important;" class=""> I was wondering the reason behind this since I have found some toolboxes for PAC that allow computing the MI
with a different selection of channels (e.g. occipital chans for phase and frontal chans for amplitude). </span><br class="">
</div>
</div>
</blockquote>
<div><br class="">
</div>
<div>OK, I did not understand your question earlier. So what you mean with ‘on different electrodes’ is to use one channel for the low frequency phase, and another for the high frequency envelope. I missed that one. As far as I know there have been some contributions
to this function (since 2017) which enable the computation of cross-channel PAC. </div>
<div><br class="">
</div>
<blockquote type="cite" class="">
<div class="">
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<br class="">
</div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<br class="">
</div>
<p class="p2" style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;">
</p>
<div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 10pt;" class=""><i class="">Q.2 When computing PAC with Fieldtrip, I get the same value for the entire frequency band of the phase (i.e. same number from 4 to 8 Hz). This is despite the resulting
MI matrix being N.channel*N.freqphase*N.freqAmplitude.</i></span></div>
<div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 10pt;" class=""><i class="">Since I would like to explore which theta frequency phase is mostly coupled with the higher frequency power, I would like to know why I get the same values and how
to fix this as I could not find any configuration about averaging frequencies (e.g. cfg.averageoverfreq = 'yes'/'no').</i></span></div>
<div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">
<i class=""><br class="">
</i></div>
<div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 10pt;" class=""><i class="">This I don’t understand. I cannot comment on this without knowing more about the exact parameters used for the generation of the input data into the ft_crossfrequencyanalysis
function.</i></span></div>
<div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">
<i class=""><br class="">
</i></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;" class="">I asked this question because, despite the output of <span style="background-color: rgb(255, 255, 255); display: inline !important;" class="">ft_crossfrequencyanalysis</span><span class="Apple-converted-space"> </span>being
chanxfreqlowxfreqhigh (180x24x51), the value is the same for all the frequencies of the phase (4-8 Hz). There is no parameter in the function to configure this option and it is indeed limiting any explorative analysis. Is there a way to get a PAC estimate
for every frequency of the phase?</span></div>
</div>
</blockquote>
<div><br class="">
</div>
<div>For me it just seems to work. That is: I never use this function myself, but I just generated some random data, and got some results with different values for 4/5/6/7/8 Hz.</div>
<div>I cannot comment on this any further, because I don’t know the specifics of your data. </div>
<blockquote type="cite" class="">
<div class="">
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<br class="">
</div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 11pt;" class=""><br class="">
</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;" class="">Q3. The last question about the statistics was because, with other PAC toolboxes, a statistic against a surrogate comodulogram with no coupling is computed and a pvalue is generated
to assess whether the PAC index is reliable or not. </span></div>
</div>
</blockquote>
<div><br class="">
</div>
<div>‘Reliable’ is not a statistical statement. As I said earlier, statistics are done in order to test the data against a certain null hypothesis. In the case of an event-related design (but also in the case of ongoing oscillations where the basic periodicity
is not a nice sinusoid), there may be all kinds of interesting across frequency non-linear interaction patterns, so rejection of a null hypothesis of CFC=0 will be trivial. Things might be a bit better if you compute across channel PAC, but as long as you
are using sensor level EEG data with a lot of spatial smearing across the scalp, I wouldn’t hold my breath.</div>
<br class="">
<blockquote type="cite" class="">
<div class="">
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;" class="">It seems that Fieldtrip does not have a function for this purpose. Also, the standard permutation statistics would require changing the structure of the data to match it with
the inputs required by spectral or time statistical analysis functions. Thus, I was wondering how to compute proper statistical testing on PAC data with Fieldtrip. </span></div>
</div>
</blockquote>
<div><br class="">
</div>
<div>It depends. If your unit-of-observation is a group comparison across two sufficiently well matchted conditions, then a surrogate strategy would not be needed, would it? If you want to compute a null distribution within a subject, trial shuffling is probably
an option, but this requires some matlab voodoo on your end.</div>
<div><br class="">
</div>
<div>Best wishes,</div>
<div>Jan-Mathijs</div>
<div><br class="">
</div>
<div><br class="">
</div>
<br class="">
<blockquote type="cite" class="">
<div class="">
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;" class="">In conclusion, if I understood your response correctly, Fieldtrip's function for computing PAC with Tort's Modulation index is not appropriate for tasks with event-related modulation
of oscillatory activity. Thus, PAC analysis should only be run on time windows where no event-related activity takes place or on resting-state data. Is that correct?</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<br class="">
</div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 11pt;" class=""><br class="">
</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;" class="">Thank you for taking the time to read my questions and responses. </span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 11pt;" class=""><br class="">
</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 11pt;" class=""><br class="">
</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;" class="">Best wishes and happy Easter,</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 11pt;" class=""><br class="">
</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;" class="">Elisa</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 11pt;" class=""><br class="">
</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 11pt;" class=""><br class="">
</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 11pt;" class=""><br class="">
</span></div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 11pt;" class=""> </span><br class="">
</div>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;" class="">
<br class="">
</div>
<p class="p2" style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;">
</p>
<p class="p2" style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 10px; line-height: normal; font-family: Courier;">
<span style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;" class=""></span></p>
<div style="margin: 0px; caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; min-height: 14px;" class="">
<br class="">
</div>
<p style="margin-top: 0px; margin-bottom: 0px; caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">
</p>
<div style="font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-family: Arial, Helvetica, sans-serif; font-size: 12pt;" class="">
<br class="">
</div>
<hr tabindex="-1" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; display: inline-block; width: 766.359375px;" class="">
<span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;" class=""></span>
<div id="divRplyFwdMsg" dir="ltr" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">
<font face="Calibri, sans-serif" style="font-size: 11pt;" class=""><b class="">From:</b><span class="Apple-converted-space"> </span>fieldtrip <<a href="mailto:fieldtrip-bounces@science.ru.nl" class="">fieldtrip-bounces@science.ru.nl</a>> on behalf of Schoffelen,
J.M. (Jan Mathijs) via fieldtrip <<a href="mailto:fieldtrip@science.ru.nl" class="">fieldtrip@science.ru.nl</a>><br class="">
<b class="">Sent:</b><span class="Apple-converted-space"> </span>Wednesday, April 13, 2022 07:59<br class="">
<b class="">To:</b><span class="Apple-converted-space"> </span>FieldTrip discussion list <<a href="mailto:fieldtrip@science.ru.nl" class="">fieldtrip@science.ru.nl</a>><br class="">
<b class="">Cc:</b><span class="Apple-converted-space"> </span>Schoffelen, J.M. (Jan Mathijs) <<a href="mailto:janmathijs.schoffelen@donders.ru.nl" class="">janmathijs.schoffelen@donders.ru.nl</a>><br class="">
<b class="">Subject:</b><span class="Apple-converted-space"> </span>Re: [FieldTrip] PAC analysis with ft_crossfrequencyanalysis</font>
<div class=""> </div>
</div>
<div class="" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; word-wrap: break-word; line-break: after-white-space;">
Hi Elisa,
<div class=""><br class="">
</div>
<div class="">Your questions are not decorated with any insights about code/data, so it’s a bit guessing as to how to compile an answer to your questions that might help you further. I’ll try anyhow:</div>
<div class="">
<div class="">
<blockquote type="cite" class="">
<div class="">
<div class="" style="font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;">
<div class="" style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;">
<ol class="">
<li class=""><span class=""><span class="" style="background-color: rgb(255, 255, 255); display: inline !important;"><span class=""> What is the minimum epoch length required to compute PAC (is 1s enough to compute the phase of 4 Hz)? <br class="">
</span></span></span></li></ol>
</div>
</div>
</div>
</blockquote>
<div class="">The sliding time window (which is not necessarily the same as the epoch length) should be sufficiently long to get a decent estimate of the phase at 4Hz. Thus, a cfg.t_ftimwin for the low frequency oscillation, to be used in ft_freqanalysis to
compute the freqlo should be sufficient. </div>
<div class=""><br class="">
</div>
<blockquote type="cite" class="">
<div class="">
<div class="" style="font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;">
<div class="" style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;">
<ol class="">
<li class="" style="display: block;"><span class=""><span class="" style="background-color: rgb(255, 255, 255); display: inline !important;"><span class=""><br class="">
</span></span></span></li><li class=""><span class=""><span class="" style="background-color: rgb(255, 255, 255); display: inline !important;"><span class="">Is this computation suitable for tasks with a strong event-related synchronization? I read that ERPs should be subtracted from
this analysis to avoid confounding effects but here I have reaching movements.</span></span></span></li></ol>
</div>
</div>
</div>
</blockquote>
<div class="">No, and subtraction of an ERP is not going to be very useful in my opinion. See: <a href="https://urldefense.com/v3/__https://www.fieldtriptoolbox.org/faq/evoked_vs_induced/__;!!HJOPV4FYYWzcc1jazlU!9SocnEHY5D4b6IoSCImxrNII9ePfLxiWSO-Bl4bagz1C_AbEfYdSngiijmxGe6qz686hKu_fPxCTB8yHpEPajhSg_5JG08Xl$" data-auth="NotApplicable" class="">https://www.fieldtriptoolbox.org/faq/evoked_vs_induced/</a></div>
<div class=""><br class="">
</div>
<blockquote type="cite" class="">
<div class="">
<div class="" style="font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;">
<div class="" style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;">
<ol class="">
<li class=""><span class=""><span class="" style="background-color: rgb(255, 255, 255); display: inline !important;"><span class="">When computing PAC with Fieldtrip, I get the same value for the entire frequency band of the phase (i.e. same number from 4 to
8 Hz). This is d<span class="" style="background-color: rgb(255, 255, 255); display: inline !important;">espite the resulting MI matrix being N.channel*N.freqphase*N.freqAmplitude.</span></span></span></span></li><li class="" style="display: block;"><span class=""><span class="" style="background-color: rgb(255, 255, 255); display: inline !important;"><span class="">Since I would like to explore which theta frequency phase is mostly coupled with the higher frequency
power, I would like to know why I get the same values and how to fix this as I could not find any configuration about averaging frequencies (e.g. cfg.averageoverfreq = 'yes'/'no').</span></span></span></li></ol>
</div>
</div>
</div>
</blockquote>
<div class="">This I don’t understand. I cannot comment on this without knowing more about the exact parameters used for the generation of the input data into the ft_crossfrequencyanalysis function.</div>
<div class=""><br class="">
</div>
<blockquote type="cite" class="">
<div class="">
<div class="" style="font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;">
<div class="" style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;">
<ol class="">
<li class="">If I manage to compute a meaningful MI, how do I statistically test whether it is significant?</li></ol>
</div>
</div>
</div>
</blockquote>
<div class="">‘Significant’ is always related to a null hypothesis. What’s your null hypothesis?</div>
<div class=""><br class="">
</div>
<blockquote type="cite" class="">
<div class="" style="font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;">
<div class="" style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;">
<ol class="">
<li class="">Last but not least, is there a physiological or computational explanation for the impossibility of computing PAC on different electrodes?</li></ol>
</div>
</div>
</blockquote>
<div class="">I don’t understand the question underlying this question: given some data, and a function, one could most of the time produce a result. In that sense it is always possible. Whether or not that result is interpretable, that’s a different question,
but it probably does not depend on whether it was computed on electrode O1, or on electrode P6</div>
<div class=""><br class="">
</div>
<div class="">Best wishes,</div>
<div class="">Jan-Mathijs</div>
<div class=""><br class="">
</div>
<br class="">
<blockquote type="cite" class="">
<div class="" style="font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;">
<div class="" style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;">
<div class=""></div>
</div>
<div id="x_Signature" class="">
<div class="">
<div class="" style="font-family: Arial, Helvetica, sans-serif; font-size: 12pt;">
</div>
<div class=""></div>
<div id="x_divtagdefaultwrapper" dir="ltr" class="" style="font-size: 12pt; font-family: Calibri, Helvetica, sans-serif;">
<div class="" style="margin-top: 0px; margin-bottom: 0px;">
<div dir="ltr" class="" style="margin: 0px; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">
<div class="" style="margin: 0px; font-family: wf_segoe-ui_normal, "Segoe UI", "Segoe WP", Tahoma, Arial, sans-serif, serif, EmojiFont; font-size: 15px; color: rgb(33, 33, 33);">
<div class="" style="margin: 0px;">
<div class="" style="margin: 0px;">
<div class="" style="margin: 0in 0in 0.0001pt;"><span class="" style="margin: 0px; font-size: 12pt;"><br class="">
</span></div>
<div class="" style="margin: 0in 0in 0.0001pt;">Thank you very much for taking the time to read my questions. I really hope to get some answers from you.</div>
<div class="" style="margin: 0in 0in 0.0001pt;"><br class="">
</div>
<div class="" style="margin: 0in 0in 0.0001pt;">Best wishes.</div>
<div class="" style="margin: 0in 0in 0.0001pt;"><br class="">
</div>
<div class="" style="margin: 0in 0in 0.0001pt;">Elisa </div>
<div class="" style="margin: 0in 0in 0.0001pt;"><br class="">
</div>
<div class="" style="margin: 0in 0in 0.0001pt;"><br class="">
</div>
<div class="" style="margin: 0in 0in 0.0001pt;"><span class="" style="margin: 0px; font-size: 11pt; color: rgb(102, 102, 102); font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif;">Elisa Tatti, Ph.D.</span></div>
<div class="" style="margin: 0in 0in 0.0001pt;"><span class="" style="margin: 0px; font-size: 11pt; color: rgb(102, 102, 102); font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif;">Post Doctoral Research Fellow </span><span class="" style="margin: 0px; font-family: "Times New Roman", serif, serif, EmojiFont; font-size: 12pt;"><u class=""></u><u class=""></u></span></div>
</div>
<span class="" style="font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif; font-size: 11pt; color: rgb(102, 102, 102);"></span>
<div class="" style="margin: 0px;">
<div class="" style="margin: 0in 0in 0.0001pt;"><span class="" style="color: rgb(102, 102, 102); font-size: 11pt; font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif;">CUNY, School of Medicine </span><br class="">
</div>
<span class="" style="font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif; font-size: 11pt; color: rgb(102, 102, 102);"></span></div>
<div class="" style="margin: 0px;"><span class="" style="font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif; font-size: 11pt; color: rgb(102, 102, 102);"></span>
<div class="" style="margin: 0in 0in 0.0001pt;"><span class="" style="margin: 0px; font-size: 11pt; color: rgb(102, 102, 102); font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif;">160 Convent ave</span><span class="" style="margin: 0px; font-family: "Times New Roman", serif, serif, EmojiFont; font-size: 12pt;"><u class=""></u><u class=""></u></span></div>
</div>
<span class="" style="font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif; font-size: 11pt; color: rgb(102, 102, 102);"></span>
<div class="" style="margin: 0px;">
<div class="" style="margin: 0in 0in 0.0001pt;"><span class="" style="margin: 0px; font-size: 11pt; color: rgb(102, 102, 102); font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif;">10031 </span><span class="" style="margin: 0px; font-family: "Times New Roman", serif, serif, EmojiFont; font-size: 12pt;"><u class=""></u><u class=""></u></span></div>
</div>
<span class="" style="font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif; font-size: 11pt; color: rgb(102, 102, 102);"></span>
<div class="" style="margin: 0px;">
<div class="" style="margin: 0in 0in 0.0001pt;"><span class="" style="margin: 0px; font-size: 11pt; color: rgb(102, 102, 102); font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif;">New York City, NY </span><span class="" style="margin: 0px; font-family: "Times New Roman", serif, serif, EmojiFont; font-size: 12pt;"><u class=""></u><u class=""></u></span></div>
</div>
<span class="" style="font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif; font-size: 11pt; color: rgb(102, 102, 102);"></span>
<div class="" style="margin: 0px;">
<div class="" style="margin: 0in 0in 0.0001pt;"><span class="" style="margin: 0px; font-size: 11pt; color: rgb(102, 102, 102); font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif;"> </span><span class="" style="margin: 0px; font-family: "Times New Roman", serif, serif, EmojiFont; font-size: 12pt;"><u class=""></u><u class=""></u></span></div>
</div>
<span class="" style="font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif; font-size: 11pt; color: rgb(102, 102, 102);"></span></div>
</div>
<span class="" style="font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif; font-size: 11pt; color: rgb(102, 102, 102);"></span>
<div class="" style="margin: 0in 0in 0.0001pt; color: rgb(33, 33, 33); font-family: wf_segoe-ui_normal, "Segoe UI", "Segoe WP", Tahoma, Arial, sans-serif, serif, EmojiFont; font-size: 15px;">
<span class="" style="margin: 0px; font-size: 11pt; color: rgb(102, 102, 102); font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif;">Tel. +1 3472043952</span></div>
<div class="" style="margin: 0in 0in 0.0001pt; color: rgb(33, 33, 33); font-family: wf_segoe-ui_normal, "Segoe UI", "Segoe WP", Tahoma, Arial, sans-serif, serif, EmojiFont; font-size: 15px;">
<span class="" style="margin: 0px; font-size: 12pt;"><br class="">
</span></div>
<p class="" style="margin: 0in 0in 0.0001pt; color: rgb(33, 33, 33); font-family: wf_segoe-ui_normal, "Segoe UI", "Segoe WP", Tahoma, Arial, sans-serif, serif, EmojiFont; font-size: 15px;">
<span class="" style="margin: 0px; font-size: 12pt;"></span></p>
<div class="" style="font-family: Calibri, Arial, Helvetica, sans-serif; text-align: start;">
<div class="" style="margin: 0px;"><span class=""><font size="2" class=""><span class="" style="font-family: Raavi, "Nirmala UI", "Gurmukhi MN", sans-serif; font-size: 11pt; color: rgb(102, 102, 102);"><i class=""> pronouns: she/her/hers</i></span></font></span></div>
</div>
<br class="">
<p class="" style="margin-top: 0px; margin-bottom: 0px;"></p>
</div>
<div class="" style="margin: 0px;">
<div class="" style="margin: 0px; color: rgb(51, 51, 51); text-align: start;"></div>
<br class="">
</div>
<br class="">
</div>
</div>
</div>
</div>
</div>
<span class="" style="font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; float: none; display: inline !important;">_______________________________________________</span><br class="" style="font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;">
<span class="" style="font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; float: none; display: inline !important;">fieldtrip
mailing list</span><br class="" style="font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;">
<a href="https://mailman.science.ru.nl/mailman/listinfo/fieldtrip" data-auth="NotApplicable" class="" style="font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;">https://mailman.science.ru.nl/mailman/listinfo/fieldtrip</a><br class="" style="font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;">
<a href="https://urldefense.com/v3/__https://doi.org/10.1371/journal.pcbi.1002202__;!!HJOPV4FYYWzcc1jazlU!5LW3HBBoemUPEhg6a_oAvt1CgyxKXM4ht3E-09jq5qNQLSuUAwlDJ4wg-LQfRQyUez2tPhThigXKwdpfytysP0iAbbWWxNcf__bmiQ$" data-auth="NotApplicable" class="" style="font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;">https://urldefense.com/v3/__https://doi.org/10.1371/journal.pcbi.1002202__;!!HJOPV4FYYWzcc1jazlU!5LW3HBBoemUPEhg6a_oAvt1CgyxKXM4ht3E-09jq5qNQLSuUAwlDJ4wg-LQfRQyUez2tPhThigXKwdpfytysP0iAbbWWxNcf__bmiQ$</a></blockquote>
</div>
</div>
</div>
</div>
</blockquote>
</div>
<br class="">
</div>
</body>
</html>