Spatial Bayesian GLM on the cortical surface produces reliable task activations in individuals and groups

• Published in: NeuroImage (Orlando, Fla.) Vol. 249; p. 118908
• Main Authors: Spencer, Daniel, Yue, Yu Ryan, Bolin, David, Ryan, Sarah, Mejia, Amanda F.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2022; Elsevier Limited; Elsevier
• Subjects: Adult; Bayes Theorem; Bayesian; Bayesian analysis; Brain research; Cerebral Cortex - diagnostic imaging; Cerebral Cortex - physiology; Connectome - methods; Connectome - standards; Cortical surface; Efficiency; General linear model; Humans; Linear Models; Magnetic Resonance Imaging - methods; Magnetic Resonance Imaging - standards; Models, Theoretical; Power; Reproducibility of Results; Sparsity; Task fMRI; Task Performance and Analysis; Cortical surface; General linear model; Task fMRI; Bayesian
• ISSN: 1053-8119; 1095-9572; 1095-9572
• DOI: 10.1016/j.neuroimage.2022.118908

•We present a fast cortical surface-based spatial Bayesian GLM for task fMRI.•Leveraging dependencies along the cortex enhances accuracy and power.•Using HCP retest data, we find more reliable activations in individuals and groups.•Power is dramatically increased compared with “massive univariate” modeling.•A user-friendly R package facilitates application to CIFTI and GIFTI-format fMRI data. [Display omitted] The general linear model (GLM) is a widely popular and convenient tool for estimating the functional brain response and identifying areas of significant activation during a task or stimulus. However, the classical GLM is based on a massive univariate approach that does not explicitly leverage the similarity of activation patterns among neighboring brain locations. As a result, it tends to produce noisy estimates and be underpowered to detect significant activations, particularly in individual subjects and small groups. A recently proposed alternative, a cortical surface-based spatial Bayesian GLM, leverages spatial dependencies among neighboring cortical vertices to produce more accurate estimates and areas of functional activation. The spatial Bayesian GLM can be applied to individual and group-level analysis. In this study, we assess the reliability and power of individual and group-average measures of task activation produced via the surface-based spatial Bayesian GLM. We analyze motor task data from 45 subjects in the Human Connectome Project (HCP) and HCP Retest datasets. We also extend the model to multi-run analysis and employ subject-specific cortical surfaces rather than surfaces inflated to a sphere for more accurate distance-based modeling. Results show that the surface-based spatial Bayesian GLM produces highly reliable activations in individual subjects and is powerful enough to detect trait-like functional topologies. Additionally, spatial Bayesian modeling enhances reliability of group-level analysis even in moderately sized samples (n=45). Notably, the power of the spatial Bayesian GLM to detect activations above a scientifically meaningful effect size is nearly invariant to sample size, exhibiting high power even in small samples (n=10). The spatial Bayesian GLM is computationally efficient in individuals and groups and is convenient to implement with the open-source BayesfMRI R package.