Template Independent Component Analysis: Targeted and Reliable Estimation of Subject-level Brain Networks Using Big Data Population Priors

• Published in: Journal of the American Statistical Association Vol. 115; no. 531; pp. 1151 - 1177
• Main Authors: Mejia, Amanda F., Nebel, Mary Beth, Wang, Yikai, Caffo, Brian S., Guo, Ying
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis 02.07.2020; Taylor & Francis Ltd
• Subjects: Algorithms; Applications and case studies; Bayesian analysis; Bayesian methods; Bayesian theory; Big Data; Brain; Brain size; Computationally intensive methods; Computer simulation; Empirical analysis; Expectation-maximization; Functional magnetic resonance imaging; humans; Independent component analysis; Magnetic resonance imaging; magnetism; Networks; Neuroimaging; Populations; Regression analysis; Reliability; Reliability analysis; Simulation; Statistical methods; Statistics; Wealth
• DOI: 10.1080/01621459.2019.1679638
• ISSN: 0162-1459; 1537-274X

Large brain imaging databases contain a wealth of information on brain organization in the populations they target, and on individual variability. While such databases have been used to study group-level features of populations directly, they are currently underutilized as a resource to inform single-subject analysis. Here, we propose leveraging the information contained in large functional magnetic resonance imaging (fMRI) databases by establishing population priors to employ in an empirical Bayesian framework. We focus on estimation of brain networks as source signals in independent component analysis (ICA). We formulate a hierarchical "template" ICA model where source signals-including known population brain networks and subject-specific signals-are represented as latent variables. For estimation, we derive an expectation-maximization (EM) algorithm having an explicit solution. However, as this solution is computationally intractable, we also consider an approximate subspace algorithm and a faster two-stage approach. Through extensive simulation studies, we assess performance of both methods and compare with dual regression, a popular but ad-hoc method. The two proposed algorithms have similar performance, and both dramatically outperform dual regression. We also conduct a reliability study utilizing the Human Connectome Project and find that template ICA achieves substantially better performance than dual regression, achieving 75-250% higher intra-subject reliability. Supplementary materials for this article, including a standardized description of the materials available for reproducing the work, are available as an online supplement.