Brain synchronizability, a false friend

TL;DR

This paper critically examines the concept of brain network synchronizability, arguing that traditional measures like the Master Stability Function are not applicable to brain dynamics and proposing alternative quantification methods.

Contribution

It challenges the use of MSF-based synchronizability in neuroscience and offers new approaches better suited to brain network analysis.

Findings

MSF formalism does not accurately reflect brain dynamics

Traditional synchronizability measures may lead to misleading conclusions

Alternative methods for quantifying brain synchronization are proposed

Abstract

Synchronization plays a fundamental role in healthy cognitive and motor function. However, how synchronization depends on the interplay between local dynamics, coupling and topology and how prone to synchronization a network with given topological organization is are still poorly understood issues. To investigate the synchronizability of both anatomical and functional brain networks various studies resorted to the Master Stability Function (MSF) formalism, an elegant tool which allows analysing the stability of synchronous states in a dynamical system consisting of many coupled oscillators. Here, we argue that brain dynamics does not fulfil the formal criteria under which synchronizability is usually quantified and, perhaps more importantly, what this measure itself quantifies refers to a global dynamical condition that never holds in the brain (not even in the most pathological conditions), and therefore no neurophysiological conclusions should be drawn based on it. We discuss the meaning of synchronizability and its applicability to neuroscience and propose alternative ways to quantify brain networks synchronization.