Critical brain dynamics at large scale

TL;DR

This paper reviews evidence that the brain operates at a critical state with power-law correlations, which is essential for adaptive behavior and information processing, supported by empirical data across multiple scales.

Contribution

It synthesizes recent empirical findings supporting the hypothesis that brain dynamics are critical, highlighting the significance of this regime for brain function.

Findings

Brain dynamics exhibit signatures of criticality across scales.

Criticality enables optimal information flow and adaptive behavior.

Empirical evidence supports the power-law correlations in brain activity.

Abstract

Highly correlated brain dynamics produces synchronized states with no behavioral value, while weakly correlated dynamics prevent information flow. In between these states, the unique dynamical features of the critical state endow the brain with properties which are fundamental for adaptive behavior. We discuss the idea put forward two decades ago by Per Bak that the working brain stays at an intermediate (critical) regime characterized by power-law correlations. This proposal is now supported by a wide body of empirical evidence at different scales demonstrating that the spatiotemporal brain dynamics exhibit key signatures of critical dynamics, previously recognized in other complex systems. The rationale behind this program is discussed in these notes, followed by an account of the most recent results.