Disentangling the critical signatures of neural activity

TL;DR

This paper investigates neural activity signatures of criticality, demonstrating that extrinsic modulation and internal interactions contribute differently to power-law avalanches and correlations, with implications for understanding brain dynamics.

Contribution

It introduces a framework distinguishing the roles of extrinsic modulation and internal interactions in neural criticality signatures, supported by data analysis and modeling.

Findings

Power-law avalanches coexist with spatial correlations characteristic of critical systems.

Extrinsic modulation causes power-law avalanches satisfying the crackling-noise relation.

Internal interactions determine scale-free correlations.

Abstract

The critical brain hypothesis has emerged as an attractive framework to understand neuronal activity, but it is still widely debated. In this work, we analyze data from a multi-electrodes array in the rat's cortex and we find that power-law neuronal avalanches satisfying the crackling-noise relation coexist with spatial correlations that display typical features of critical systems. In order to shed a light on the underlying mechanisms at the origin of these signatures of criticality, we introduce a paradigmatic framework with a common stochastic modulation and pairwise linear interactions inferred from our data. We show that in such models power-law avalanches that satisfy the crackling noise relation emerge as a consequence of the extrinsic modulation, whereas scale-free correlations are solely determined by internal interactions. Moreover, this disentangling is fully captured by the mutual information in the system. Finally, we show that analogous power-law avalanches are found in more realistic models of neural activity as well, suggesting that extrinsic modulation might be a broad mechanism for their generation.