The brain: What is critical about it?

TL;DR

This paper reviews the hypothesis that the brain operates near a second order phase transition, which enables robust and flexible behavior through a rich landscape of metastable states.

Contribution

It synthesizes recent theoretical and empirical evidence supporting the criticality hypothesis as fundamental to brain function.

Findings

Brain properties linked to criticality enhance behavioral flexibility.

Criticality provides a large repertoire of metastable states.

Recent results support the brain's operation near a phase transition.

Abstract

We review the recent proposal that the most fascinating brain properties are related to the fact that it always stays close to a second order phase transition. In such conditions, the collective of neuronal groups can reliably generate robust and flexible behavior, because it is known that at the critical point there is the largest abundance of metastable states to choose from. Here we review the motivation, arguments and recent results, as well as further implications of this view of the functioning brain.