Scaling and organization of electroencephalographic background activity and alpha rhythm in healthy young adults

Abstract

The coexistence of the broad-band fluctuation and α rhythm of the brain dynamics is studied based on the zero-crossing property of the local electroencephalographic (EEG) recording in eyes closed and eyes open. A two-component zero-crossing scenario, consisting of a broad-band fractal and narrow-band rhythm components, is assumed. Scaling is found in the power law distribution p(τ) ~ τ ^−ν of the crossing time interval τ of the broad-band fluctuation. In α dominant brain state, the α rhythm interval L also exhibits scaling in the form of power law distribution: $p(L) ~ L^\phi$. Our main result is the relationship $\nu+\phi ~ 3$ that characterizes the organization of these two prominent features of the brain dynamics. The possible role of self-organized criticality of punctuated equilibrium in this organization is discussed.