# [FieldTrip] Intratrial phase coherence (phase concentration) for a broad range of frequencies

Saman Abbaspoor sabbaspoor.neusci at gmail.com
Tue Dec 3 19:55:23 CET 2019

```*Dear Fieldtrip family,*

As part of my project, I would like to use Fieldtrip to plot phase
concentration for a range of frequency (3 - 9 Hz) over the whole time
length of a signal. I am trying to generate figure 3A on the following
paper: https://www.jneurosci.org/content/31/50/18423.short

This instantaneous phase should be for a broad range of frequencies (3 - 9
Hz) not a specific frequency (e.g. 3Hz).

I have read on one of your email discussions that I can use the following
approach:
1 - Do the time-frequency analysis
3 - take the instantaneous phase by using "*angle*" in Matlab
4 - Then use "*circ_r*" in circular statics toolbox (or using the
formula: *abs(mean(exp(1i
* Phase), 1))* )
5 - Plot over time

Yet, this will give me the frequency-specific phases that I am not looking
for. I am looking for phase concentration for a broad frequency band.

My approach was to:
1 - Filter the data in the frequency range of interest using a Butterworth
filter
2 - take the Hilbert Transform of the signals (*hilbert* function in Matlab)
3 - take the instantaneous phase by using "*angle*" in Matlab
4 - Then use "*circ_r*" in circular statics toolbox (or using the
formula: *abs(mean(exp(1i
* Phase), 1))* )
5 - Plot over time

It gives me some strange looking results that might get fixed by binning
the angular data.

I would like to know how I can implement this analysis in Fieldtrip.

Looking forward to hearing from you.

Best regards,

*SAM*

Saman Abbaspoor
Ph.D. Student | Vanderbilt University | Psychological Sciences Department
*mobile: (615) 705-94 <(615)+238-7261>16*
*email: saman.abbaspoor at vanderbilt.com <saman.abbaspoor at vanderbilt.com>*
*skype: saman95abbaspour*
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