Two Sample Test for Eigendecompositions of Functional Data

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Hauptverfasser: de la Garza, Angel Garcia, Sauerbrei, Britton, Goldsmith, Jeff
Format: Preprint
Veröffentlicht: 2026
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author de la Garza, Angel Garcia
Sauerbrei, Britton
Goldsmith, Jeff
author_facet de la Garza, Angel Garcia
Sauerbrei, Britton
Goldsmith, Jeff
contents Neuron-level firing data is believed to be governed by latent activation patterns during task completion. Analysing repeated trials of a task allows us to study these patterns, typically by averaging in-vivo neural spikes across trials. However, estimates of underlying latent activation patterns show trial-to-trial variability. Our aim is to determine whether this variation arises from observed data differences or changes in the latent activation patterns themselves. The latter would imply that current approaches overlook meaningful activation changes, necessitating adjustments in dimension reduction and downstream analysis. We propose a test that compares the eigendecompositions of two samples of functional data based on the covariance matrix of scores derived from a functional principal component analysis of the pooled data. Initially developed for independent samples, we later extend the test to paired samples, as necessary for our data. Simulation studies demonstrate its superior power compared to leading methods across various scenarios. In an experiment with 157 trials, we analyse all pairwise comparisons using a permutation approach to test the null hypothesis of shared latent activation patterns across trials. Our findings reveal trial-to-trial variation in latent activation patterns that cannot be attributed to sampling noise.
format Preprint
id arxiv_https___arxiv_org_abs_2604_00220
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Two Sample Test for Eigendecompositions of Functional Data
de la Garza, Angel Garcia
Sauerbrei, Britton
Goldsmith, Jeff
Methodology
Applications
Neuron-level firing data is believed to be governed by latent activation patterns during task completion. Analysing repeated trials of a task allows us to study these patterns, typically by averaging in-vivo neural spikes across trials. However, estimates of underlying latent activation patterns show trial-to-trial variability. Our aim is to determine whether this variation arises from observed data differences or changes in the latent activation patterns themselves. The latter would imply that current approaches overlook meaningful activation changes, necessitating adjustments in dimension reduction and downstream analysis. We propose a test that compares the eigendecompositions of two samples of functional data based on the covariance matrix of scores derived from a functional principal component analysis of the pooled data. Initially developed for independent samples, we later extend the test to paired samples, as necessary for our data. Simulation studies demonstrate its superior power compared to leading methods across various scenarios. In an experiment with 157 trials, we analyse all pairwise comparisons using a permutation approach to test the null hypothesis of shared latent activation patterns across trials. Our findings reveal trial-to-trial variation in latent activation patterns that cannot be attributed to sampling noise.
title Two Sample Test for Eigendecompositions of Functional Data
topic Methodology
Applications
url https://arxiv.org/abs/2604.00220