Conserved Ising Model on the Human Connectome

TL;DR

This study compares the Ising model's spin correlations with empirical brain functional correlations, revealing increased alignment at the modular level during anesthesia and highlighting the significance of criticality in brain dynamics.

Contribution

It demonstrates that the match between structural and functional brain correlations peaks at criticality, providing insights into brain dynamics under anesthesia.

Findings

Better correlation match at modular level during anesthesia

Peak correlation at critical state (peak of specific heat)

Brain dynamics under anesthesia deviate from criticality

Abstract

Dynamical models implemented on the large scale architecture of the human brain may shed light on how function arises from the underlying structure. This is the case notably for simple abstract models, such as the Ising model. We compare the spin correlations of the Ising model and the empirical functional brain correlations, both at the single link level and at the modular level, and show that their match increases at the modular level in anesthesia, in line with recent results and theories. Moreover, we show that at the peak of the specific heat (the \it{critical state}) the spin correlations are minimally shaped by the underlying structural network, explaining how the best match between structure and function is obtained at the onset of criticality, as previously observed. These findings confirm that brain dynamics under anesthesia shows a departure from criticality and could open the way to novel perspectives when the conserved magnetization is interpreted in terms of an homeostatic principle imposed to neural activity.