Credible rectangles for high-dimensional posterior comparison

Fuente: arXiv
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Main Authors: Chevaux, Alice, Arbel, Julyan, King, Guillaume Kon Kam, Achard, Sophie
Format: Preprint
Published: 2026
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author Chevaux, Alice
Arbel, Julyan
King, Guillaume Kon Kam
Achard, Sophie
author_facet Chevaux, Alice
Arbel, Julyan
King, Guillaume Kon Kam
Achard, Sophie
contents We propose a Bayesian framework for uncertainty quantification and comparison in brain connectivity graph analysis. Standard graph-based approaches typically rely on point estimates of correlation matrices, overlooking the uncertainty induced by high-dimensional estimation from limited data. Our methodology constructs and compares credible hyperrectangles derived from posterior distributions, providing interpretable tools for subject-level inference and longitudinal monitoring. We develop scalable algorithms for estimating these regions in high dimensions and establish theoretical guarantees in the inverse-Wishart model for resting-state fMRI data, including a Bernstein--von Mises theorem for correlation matrices and control of a Bayesian family-wise error rate. The proposed framework enables principled detection of significant connectivity differences both globally and locally while preserving joint dependency structures. While demonstrating competitive performance against multiple-testing procedures on synthetic datasets, our approach also facilitates the direct comparison of two distinct scans from a single patient, a capability currently absent from the literature. We leverage this novelty on real datasets to improve interpretability. Beyond fMRI data, the approach provides a general framework for comparison problems in high-dimensional dependent settings.
format Preprint
id arxiv_https___arxiv_org_abs_2605_30072
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Credible rectangles for high-dimensional posterior comparison
Chevaux, Alice
Arbel, Julyan
King, Guillaume Kon Kam
Achard, Sophie
Methodology
We propose a Bayesian framework for uncertainty quantification and comparison in brain connectivity graph analysis. Standard graph-based approaches typically rely on point estimates of correlation matrices, overlooking the uncertainty induced by high-dimensional estimation from limited data. Our methodology constructs and compares credible hyperrectangles derived from posterior distributions, providing interpretable tools for subject-level inference and longitudinal monitoring. We develop scalable algorithms for estimating these regions in high dimensions and establish theoretical guarantees in the inverse-Wishart model for resting-state fMRI data, including a Bernstein--von Mises theorem for correlation matrices and control of a Bayesian family-wise error rate. The proposed framework enables principled detection of significant connectivity differences both globally and locally while preserving joint dependency structures. While demonstrating competitive performance against multiple-testing procedures on synthetic datasets, our approach also facilitates the direct comparison of two distinct scans from a single patient, a capability currently absent from the literature. We leverage this novelty on real datasets to improve interpretability. Beyond fMRI data, the approach provides a general framework for comparison problems in high-dimensional dependent settings.
title Credible rectangles for high-dimensional posterior comparison
topic Methodology
url https://arxiv.org/abs/2605.30072