Chaos Solitons & Fractals
May 30, 2026
Tales Ramos Monteiro Dos Santos, Draulio B Araujo, Helcio Felippe et al.
Psychedelic states offer a useful setting for studying changes in large-scale brain organization. Here, we applied Topological Data Analysis (TDA) to resting-state fMRI functional connectivity from nine participants scanned before and after Ayahuasca ingestion. Vietoris–Rips filtrations were constructed from correlation-derived dissimilarity matrices, and persistent entropy was used to quantify...
Journal of Physics Complexity
March 1, 2023
Aline Viol, G. M. Viswanathan, Oleksandra Soldatkina et al.
4 citations
Abstract The physical basis of consciousness is one of the most intriguing open questions that contemporary science aims to solve. By approaching the brain as an interactive information system, complex network theory has greatly contributed to understand brain process in different states of mind. We study a non-ordinary state of mind by comparing resting-state functional brain networks of...
Europhysics Letters
January 24, 2023
Helcio Felippe, Aline Viol, Dráulio Barros de Araújo et al.
9 citations
Abstract There is demand in diverse fields for a reliable method of estimating the entropy associated with correlations. The estimation of a unique entropy directly from the Pearson correlation matrix has remained an open problem for more than half a century. All existing approaches lack generality insofar as they require thresholding choices that arbitrarily remove possibly important...
arXiv Preprint Archive
July 28, 2022
Aline Viol, Gandhi M. Viswanathan, Oleksandra Soldatkina et al.
The physical basis of consciousness is one of the most intriguing open questions that contemporary science aims to solve. By approaching the brain as an interactive information system, complex network theory has greatly contributed to understand brain process in different states of mind. We study an non-ordinary state of mind by comparing resting-state functional brain networks of individuals...
Entropy
January 30, 2019
Aline Viol, Fernanda Palhano-Fontes, Heloisa Onias et al.
37 citations
With the aim of further advancing the understanding of the human brain’s functional connectivity, we propose a network metric which we term the geodesic entropy. This metric quantifies the Shannon entropy of the distance distribution to a specific node from all other nodes. It allows to characterize the influence exerted on a specific node considering statistics of the overall network...
arXiv Preprint Archive
September 26, 2018
Aline Viol, Fernanda Palhano-Fontes, Heloisa Onias et al.
Open problems abound in the theory of complex networks, which has found successful application to diverse fields of science. With the aim of further advancing the understanding of the brain's functional connectivity, we propose to evaluate a network metric which we term the geodesic entropy. This entropy, in a way that can be made precise, quantifies the Shannon entropy of the distance...
arXiv Preprint Archive
November 1, 2016
Aline Viol, Fernanda Palhano-Fontes, Heloisa Onias et al.
154 citations
The entropic brain hypothesis holds that the key facts concerning psychedelics are partially explained in terms of increased entropy of the brain's functional connectivity. Ayahuasca is a psychedelic beverage of Amazonian indigenous origin with legal status in Brazil in religious and scientific settings. In this context, we use tools and concepts from the theory of complex networks to analyze...