Assessing (im)balance in signed brain networks

Fuente: arXiv
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Autori principali: Di Vece, Marzio, Agrimi, Emanuele, Tatullo, Samuele, Gili, Tommaso, Ibáñez-Berganza, Miguel, Squartini, Tiziano
Natura: Preprint
Pubblicazione: 2025
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author Di Vece, Marzio
Agrimi, Emanuele
Tatullo, Samuele
Gili, Tommaso
Ibáñez-Berganza, Miguel
Squartini, Tiziano
author_facet Di Vece, Marzio
Agrimi, Emanuele
Tatullo, Samuele
Gili, Tommaso
Ibáñez-Berganza, Miguel
Squartini, Tiziano
contents Many complex systems - be they financial, natural, or social - are composed of units - such as stocks, neurons, or agents - whose joint activity can be represented as a multivariate time series. An issue of both practical and theoretical importance concerns the possibility of inferring the presence of a static relationship between any two units solely from their dynamic state. The present contribution aims at tackling such an issue within the frame of traditional hypothesis testing: briefly speaking, our suggestion is that of linking any two units if behaving in a sufficiently similar way. To achieve such a goal, we project a multivariate time series onto a signed graph by i) comparing the empirical properties of the former with those expected under a suitable benchmark and ii) linking any two units with a positive (negative) edge in case the corresponding series shares a significantly large number of concordant (discordant) values. To define our benchmarks, we adopt an information-theoretic approach that is rooted into the constrained maximisation of Shannon entropy, a procedure inducing an ensemble of multivariate time series that preserves some of the empirical properties on average, while randomising everything else. We showcase the possible applications of our method by addressing one of the most timely issues in the domain of neurosciences, i.e. that of determining if brain networks are frustrated or not, and, if so, to what extent. As our results suggest, this is indeed the case, with the major contribution to the underlying negative subgraph coming from the subcortical structures (and, to a lesser extent, from the limbic regions). At the mesoscopic level, the minimisation of the Bayesian Information Criterion, instantiated with the Signed Stochastic Block Model, reveals that brain areas gather into modules aligning with the statistical variant of the Relaxed Balance Theory.
format Preprint
id arxiv_https___arxiv_org_abs_2508_00542
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Assessing (im)balance in signed brain networks
Di Vece, Marzio
Agrimi, Emanuele
Tatullo, Samuele
Gili, Tommaso
Ibáñez-Berganza, Miguel
Squartini, Tiziano
Physics and Society
Information Theory
Data Analysis, Statistics and Probability
Medical Physics
Methodology
Many complex systems - be they financial, natural, or social - are composed of units - such as stocks, neurons, or agents - whose joint activity can be represented as a multivariate time series. An issue of both practical and theoretical importance concerns the possibility of inferring the presence of a static relationship between any two units solely from their dynamic state. The present contribution aims at tackling such an issue within the frame of traditional hypothesis testing: briefly speaking, our suggestion is that of linking any two units if behaving in a sufficiently similar way. To achieve such a goal, we project a multivariate time series onto a signed graph by i) comparing the empirical properties of the former with those expected under a suitable benchmark and ii) linking any two units with a positive (negative) edge in case the corresponding series shares a significantly large number of concordant (discordant) values. To define our benchmarks, we adopt an information-theoretic approach that is rooted into the constrained maximisation of Shannon entropy, a procedure inducing an ensemble of multivariate time series that preserves some of the empirical properties on average, while randomising everything else. We showcase the possible applications of our method by addressing one of the most timely issues in the domain of neurosciences, i.e. that of determining if brain networks are frustrated or not, and, if so, to what extent. As our results suggest, this is indeed the case, with the major contribution to the underlying negative subgraph coming from the subcortical structures (and, to a lesser extent, from the limbic regions). At the mesoscopic level, the minimisation of the Bayesian Information Criterion, instantiated with the Signed Stochastic Block Model, reveals that brain areas gather into modules aligning with the statistical variant of the Relaxed Balance Theory.
title Assessing (im)balance in signed brain networks
topic Physics and Society
Information Theory
Data Analysis, Statistics and Probability
Medical Physics
Methodology
url https://arxiv.org/abs/2508.00542