Spontaneous brain activity as a source of ideal1/fnoise

Abstract

We study the electroencephalogram ͑EEG͒ of 30 closed-eye awake subjects with a technique of analysis recently proposed to detect punctual events signaling rapid transitions between different metastable states. After single-EEG-channel event detection, we study global properties of events simultaneously occurring among two or more electrodes termed coincidences. We convert the coincidences into a diffusion process with three distinct rules that can yield the same only in the case where the coincidences are driven by a renewal process. We establish that the time interval between two consecutive renewal events driving the coincidences has a waiting-time distribution with inverse power-law index Ϸ 2 corresponding to ideal 1 / f noise. We argue that this discovery, shared by all subjects of our study, supports the conviction that 1 / f noise is an optimal communication channel for complex networks as in art or language and may therefore be the channel through which the brain influences complex processes and is influenced by them.

The emergence of self-organization in complex systems–Preface

“…Consequently, the dynamics of this class of complex systems are characterized by a birth-death intermittent process of cooperation, which is modeled through a renewal point process [1]. This important property is often found in biological complex systems and it is characterized by a fractal (inverse power-law) distribution of the inter-event times (see, e.g, [2,3,4,5]). …”

Scaling law of diffusivity generated by a noisy telegraph signal with fractal intermittency

“…weight of long WTs, so that the time-averaged computation results in long-range correlations also in time series with renewal events [16]. This is related to the time evolution of the rate of event production r(t), which is essentially the mean number of events per time unit [8,10,17].…”

“…There are several examples of complex systems displaying a fractal intermittent behavior: ecological systems [22], neural dynamics [23], blinking quantum dots [24,25,26], social dynamics [27], brain information processing [28,29,30,16,31,32,18,19,33,1,3,4], atmospheric turbulence [34,17,35,9], earthquakes [36], single particle tracking in cell biology [37], molecular biology [20].…”

“…[16], where a concept of global event has been used in order to characterize the overall brain complexity of healthy people. These findings are in agreement with other, better known, complexity measures, such as the long-range (power-law) correlations in both time and space [16]. The complexity index was not estimated directly from the WT-PDF, but through a different approach, which will be denoted here as Event-Driven Diffusion Scaling (EDDiS).…”

“…Details can be found in Refs. [16,9] and references therein. Most of the analytical results this method is based on were originally reported either in [46] or in [47].…”