Discussing different methods of calculating Phase Amplitude Coupling
- CWT & MVL
- Rid-rihaczek (old version, supposed to have implementation bug) & MVL
- Rid-rihaczek (new version (neuroFreq), First tf-decomposition, then windowing) & MVL
- Rid-rihaczek (old version, correctred versio) & MVL
- Rid-rihaczek (new version (neuroFreq), First windowing, then tf-decomposition) & MVL
- CWT & MI
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Synthesizing the signal:
- The phase amplitude coupled signal has been generated following proposed method at the this article.
- Generating a signal composed of:
- Random gaussian nosie of 1 second
- coupled signal one:
- Amplitude frequency: 40 Hz
- Phase frequency: 5 Hz
- coupled signal two:
- Amplitude frequency: 60 Hz
- Phase frequency: 9 Hz
- coupled signal one + additive noise
- coupled signal two + additive noise
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PAC Comodulogram
- Generating comodulogram for each of the 5 sections of the signal
-
PAC dynamic
- Generating PAC dynamic through all of the 5 second signal
- Window length = 200 ms
- Window shift step = 100 ms
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Statistical test
- Sample size: 100
- Population 1:
- Coupled signals:
- Random Phase freq in range: [4, 7]
- Random Amp freq in range: [38, 42]
- Coupled signals:
- Population 2:
- Coupled signals:
- Random Phase freq in range: [8, 11]
- Random Amp freq in range: [55, 65]
- Coupled signals:
- Null hypothesis:
- PAC in range [4,8] and [35, 45] is higher for second population
- Each of these methods has their own pros and cons
- Rid-rihaczek can decompose frequency more precicely than the CWT. The CWT will skew the freuqency axes
- MVL method is biased with amplitude signal and power (Note the comodulograms)
- MI requires signals long enough (more than 500 samples)
- MVL may detect fake couplings too but works preciecly well with actual couplings
- MVL doesn't require permutations test but using it may lead to better results espcially when we use CWT
- Curerntly MVL is much faster than MI