Does the 1/f frequency-scaling of brain signals reflect self-organized critical states?

TL;DR

This paper investigates whether the 1/f frequency scaling observed in brain signals indicates self-organized critical states, finding that while global signals show 1/f scaling, neuronal activity does not support the criticality hypothesis, and proposing an alternative model.

Contribution

The study clarifies that 1/f scaling in brain signals does not necessarily reflect critical states and introduces a new testable model explaining 1/f scaling without criticality.

Findings

Global brain signals exhibit 1/f scaling in certain frequency bands.

Neuronal activity does not align with self-organized critical states.

A new model explains 1/f scaling independently of criticality.

Abstract

Many complex systems display self-organized critical states characterized by 1/f frequency scaling of power spectra. Global variables such as the electroencephalogram, scale as 1/f, which could be the sign of self-organized critical states in neuronal activity. By analyzing simultaneous recordings of global and neuronal activities, we confirm the 1/f scaling of global variables for selected frequency bands, but show that neuronal activity is not consistent with critical states. We propose a model of 1/f scaling which does not rely on critical states, and which is testable experimentally.