Multichannel EEG Signal Recording Analysis based on Cross Frequency Coupling Method

Cross-frequency coupling (CFCo) could be important to study task-relevant manner changes in time series (TS). CFCo might also serve as an instrument to distinguish between oscillatory states and interrelations in signals, and to exhibit characteristic changes. Presenting the use of phase-amplitude type Cross Frequency Coupling, named Phase-Amplitude-Coupling (PAC) is the objective of this presentation. PAC describes the statistical dependence between the phase of a low-frequency brain rhythm and the amplitude (or power) of the higher-frequency component of electrical activity in the brain. Two other varieties of signal coupling are possible. These are the cross-frequency phase synchronization (phase-phase CFCo) and cross-frequency amplitude envelope correlation (amplitude-amplitude CFCo). These procedures should be efficient to study possible mechanism to regulate interrelation of the multichannel recorded EEG signals. As it is known, EEG signals are nonlinear and non-stationary signals. Interdependence of the different frequency range EEG signals, must be studied to understand internal behaviour of signals generated by different cortical areas.The paper is based on multichannel EEG recordings. It is possible to detect correlations between distal cortical regions during different task related events as Event Related Potentials (ERP). Correlation factor of left-right hemisphere's signals, recorded in biologically symmetric scalp positions are important in ERP studies. The Hilbert transform based method is also involved to have a way to analyze the interrelations of different brain region activities.