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Helcio Felippe

2 papers in the library · 9 citations · publishing 2023-2026

Papers

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An exploratory persistent-homology analysis of resting-state fMRI functional connectivity under Ayahuasca

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...

Threshold-free estimation of entropy from a Pearson matrix

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...