Theory of frequency modulation of electroencephalogram (EEG) in human brain with/without photo-stimulation
is presented. Firstly, physical/physiological significance of frequency modulation is discussed based on EEG data
in the state of closed eyes at rest. Secondly, possible phenomenological theoretical models under photo-stimulation
(PS) are examined to explain the features of intrinsic/induced frequency modulation and the frequency responses
induced by PS. Properties of a generalized Kubo oscillator with a parametric periodic driving force are demonstrated
to give the qualitative understandings of the observed age-dependent and light-induced natures of EEGs.
We have studied the memory effect on typical complex measures such as fractal dimension and entropy based on the sample entropy algorithm. First, it is shown how is the stochastic process of complex measures (a local fractal dimension and a local sample entropy) for real EEG data from healthy people and demented ones. The features of multi-scale entropy for EEGs are also shown. Then, the natures of complex measures for theoretical models such as Brownian oscillators and stochastic complex Ginzburg-Landau equation are exhibited. The memory effects on the complex measures for real EEG data are discussed by comparing theoretical models.