A power-law distribution of phase-locking intervals does not imply critical interaction

TL;DR

This paper challenges the idea that power-law distributions of phase-locking intervals indicate critical brain interactions, showing such patterns can arise without criticality, while global lability better distinguishes true critical states.

Contribution

It demonstrates that power-law distributions of phase-locking intervals can occur in non-critical systems, questioning their use as sole indicators of critical brain dynamics.

Findings

Pooling non-critical phase-locking intervals can produce power-law-like distributions.

Global lability of synchronisation better discriminates critical from non-critical interactions.

Power-law patterns alone do not confirm criticality in neural systems.

Abstract

Neural synchronisation plays a critical role in information processing, storage and transmission. Characterising the pattern of synchronisation is therefore of great interest. It has recently been suggested that the brain displays broadband criticality based on two measures of synchronisation - phase locking intervals and global lability of synchronisation - showing power law statistics at the critical threshold in a classical model of synchronisation. In this paper, we provide evidence that, within the limits of the model selection approach used to ascertain the presence of power law statistics, the pooling of pairwise phase-locking intervals from a non-critically interacting system can produce a distribution that is similarly assessed as being power law. In contrast, the global lability of synchronisation measure is shown to better discriminate critical from non critical interaction.