Statistical Tests for Force Inference in Heterogeneous Environments

Alexander S Serov (1) , François Laurent (1) , Charlotte Floderer (2) , Karen Perronet (3) , Cyril Favard (2) , Delphine Muriaux (2) , Nathalie Westbrook (3) , Christian L. Vestergaard (1) , Jean-Baptiste Masson (1)

1 Décision et processus Bayesiens - Decision and Bayesian Computation
2 IRIM - Institut de Recherche en Infectiologie de Montpellier
3 Laboratoire Charles Fabry / Biophotonique

We devise a method to detect and estimate forces in a heterogeneous environment based on experimentally recorded stochastic trajectories. In particular, we focus on systems modeled by the heterogeneous overdamped Langevin equation. Here, the observed drift includes a "spurious" force term when the diffusivity varies in space. We show how Bayesian inference can be leveraged to reliably infer forces by taking into account such spurious forces of unknown amplitude as well as experimental sources of error. The method is based on marginalizing the force posterior over all possible spurious force contributions. The approach is combined with a Bayes factor statistical test for the presence of forces. The performance of our method is investigated analytically, numerically and tested on experimental data sets. The main results are obtained in a closed form allowing for direct exploration of their properties and fast computation. The method is incorporated into TRamWAy, an open-source software platform for automated analysis of biomolecule trajectories.

Mots clés: biomolecule dynamics; inverse problems; Bayesian inference; overdamped Langevin equation; random walks; Itô-Stratonovich dilemma

Domaines: Physique [physics]; Statistiques [stat]

Alexander S Serov, François Laurent, Charlotte Floderer, Karen Perronet, Cyril Favard, et al.. Statistical Tests for Force Inference in Heterogeneous Environments. Scientific Reports, 2020, 10 (1), pp.3783. ⟨10.1038/s41598-020-60220-1⟩. ⟨pasteur-02865729⟩