Quantitative parameters characterizing transient processes of mastering and forgetting of photostimulation (PST) rhythms for a nonstationary electroencephalogram (EEG) are developed on the basis of a continuous wavelet transformation. Nonstationarity factor K_(nst)(μ), as well as rhythm mastering K_M(μ) and confinement K_C(μ) factors are calculated for various spectral ranges μ. Photoflash mastering time τ_M = τ_S + τ_I, which is the sum of latent silence period τ_S after PST actuation and the rhythm increasing period τ_I is calculated. In the case of PST, the EEG rhythm retardation time τ_R relative to the beginning of PST is calculated. Rhythm forgetting time τ_F = τ_P + τ_D after PST actuation is the sum of the preservation time τ_P of the corresponding rhythm over a certain time interval and its decay period τ_D. The lag time τ_L of the EEG signal relative to the PST signal after its removal is determined. The proposed method is used in quantitative analysis and classification of transient processes characterizing the properties of the central nervous system. Possible applications of the method in analysis of various nonstationary signals in physics are discussed.
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