Dear Saurabh,
The example in last year’s powerpoint presentation is the most detailed description we have available at the moment. The frequency windows in that example are based on the computation of phase-amplitude coupling between the phase of alpha/beta frequencies and the amplitude of high-frequency oscillations (200-400Hz) in the subthalamic nucleus of Parkinson’s disease patients (see also van Wijk et al. 2015 J Neurosci Methods). As it’s often a priori unknown for which frequency combinations any cross-frequency coupling occurs, one would explore a range of phase and amplitude frequency combinations resulting in a frequency-frequency spectrum. That is why the frequency values are a vector in the ppt example. The frequency resolution refers to the bandwidth of the bandpass filter and is +/- .. Hz around the center frequency (= around each of the frequencies specified in the vector). The bandwidth for the amplitude frequencies should be relatively wide in order to be able to detect fluctuations in the continuous amplitude at the phase frequency (see also Berman et al. 2012 Brain Connectivity). By contrast, the bandwidth for extracting the continuous phase should be relatively narrow. In the CFC batch, the frequency window specifies the frequency range for which CFC should be computed (provided the amplitude or phase has been extracted for any frequencies in this range in the previous time-frequency step). Hope this is helpful. I’m also happy to send you the batch .mat file corresponding to the example in the ppt if you like.
Best,
Bernadette
> On 27 Mar 2018, at 11:02, Saurabh Sonkusare <[log in to unmask]> wrote:
>
> Hi,
>
> Is there some documentation on how to perform cross frequency coupling? All I could find was a ppt showing some steps but without details. Specifically, help on "frquency window" informs that just a low cutoff and high cut off of frequency values are to provided but in the ppt its a vector for amplitude and phase and the vector size is not the same for them. Also the frequency resolution for amplitude is 35 and that for phase is 0.5. Moreover, after getting amplitude and phase information, when we move on to the actual CFC, the frequency window of amplitude series is [200 400]...can I know what this range represents.
>
> Thanks in advance.
>
> Best,
> Saurabh
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