Increasing robustness of pairwise methods for effective connectivity in Magnetic Resonance Imaging by using fractional moment series of BOLD signal distributions

TL;DR

This paper presents a novel classifier based on fractional moments of BOLD signal distributions to improve the accuracy and robustness of effective connectivity inference in fMRI data, outperforming existing methods especially under confounding noise.

Contribution

Introduces a new classifier using fractional moments and cumulants of BOLD signals, enhancing robustness and accuracy in effective connectivity estimation in fMRI.

Findings

Outperforms existing methods on benchmark datasets.

More resilient to confounding effects like differential noise.

Effective in inferring causal directionality in brain networks.

Abstract

Estimating causal interactions in the brain from functional magnetic resonance imaging (fMRI) data remains a challenging task. Multiple studies have demonstrated that all current approaches to determine direction of connectivity perform poorly even when applied to synthetic fMRI datasets. Recent advances in this field include methods for pairwise inference, which involve creating a sparse connectome in the first step, and then using a classifier in order to determine the directionality of connection between of every pair of nodes in the second step. In this work, we introduce an advance to the second step of this procedure, by building a classifier based on fractional moments of the BOLD distribution combined into cumulants. The classifier is trained on datasets generated under the Dynamic Causal Modeling (DCM) generative model. The directionality is inferred based upon statistical dependencies between the two node time series, e.g. assigning a causal link from time series of low variance to time series of high variance. Our approach outperforms or performs as well as other methods for effective connectivity when applied to the benchmark datasets. Crucially, it is also more resilient to confounding effects such as differential noise level across different areas of the connectome.