Dynamics in cortical activity revealed by resting-state MEG rhythms

TL;DR

This study uses MEG data, information theory, and network science to analyze the spatio-temporal dynamics of resting-state brain activity, revealing the posterior cortex's key role and band-specific order relations.

Contribution

It introduces a novel approach combining entropy, complexity, and network analysis to characterize resting-state cortical dynamics across frequency bands.

Findings

Posterior cortex shows stronger dynamics and high clustering in alpha band.

Order relations between entropy and complexity suggest emergent phenomena per frequency band.

First application of information theory and network science to MEG resting-state analysis.

Abstract

The brain may be thought of as a many-body architecture with a spatio-temporal dynamics described by neuronal structures. The oscillatory nature of brain activity allows these structures (nodes) to be described as a set of coupled oscillators forming a network where the node dynamics, and that of the network topology can be studied. Quantifying its dynamics at various scales is an issue that claims to be explored for several brain activities, e.g., activity at rest. The resting-state associates the underlying brain dynamics of healthy subjects that are not actively compromised with sensory or cognitive processes. Studying its dynamics is highly non-trivial but opens the door to understand the general principles of brain functioning. We hypothesize about how could be the spatio-temporal dynamics of cortical fluctuations for healthy subjects at resting-state. We retrieve the alphabet that reconstructs the dynamics (entropy/complexity) of magnetoencephalograpy signals. We assemble the cortical connectivity to elicit the network's dynamics. We depict an order relation between entropy/complexity for frequency bands. We unveiled that the posterior cortex conglomerates nodes with both stronger dynamics and high clustering for {\alpha} band. The existence of these order relations suggests an emergent phenomenon of each band. Interestingly, we find that the posterior cortex plays a cardinal role in both the dynamics and structure regarding the resting-state. To the best of our knowledge, this is the first study with magnetoencephalograpy involving information theory and network science to better understand the dynamics and structure of brain activity at rest for different bands and scales.