A devil's advocate view on 'self-organized' brain criticality

TL;DR

This paper argues that brain criticality is better understood as a self-regulated process driven by functional requirements, rather than a self-organized criticality arising from evolutionary advantages, emphasizing the importance of stationarity for brain function.

Contribution

It challenges the common notion of self-organized criticality in the brain, proposing that criticality results from functional regulation rather than autonomous self-organization.

Findings

Critical brain dynamics are driven by functional regulation, not self-organization.

Stationarity of brain activity requires operation near criticality.

Benefits of criticality are side effects, not evolutionary drivers.

Abstract

Stationarity of the constituents of the body and of its functionalities is a basic requirement for life, being equivalent to survival in first place. Assuming that the resting state activity of the brain serves essential functionalities, stationarity entails that the dynamics of the brain needs to be regulated on a time-averaged basis. The combination of recurrent and driving external inputs must therefore lead to a non-trivial stationary neural activity, a condition which is fulfilled for afferent signals of varying strengths only close to criticality. In this view, the benefits of working vicinity of a second-order phase transition, such as signal enhancements, are not the underlying evolutionary drivers, but side effects of the requirement to keep the brain functional in first place. It is hence more appropriate to use the term 'self-regulated' in this context, instead of 'self-organized'.