Open this publication in new window or tab >>2020 (English)In: Journal of Neuroscience Methods, ISSN 0165-0270, E-ISSN 1872-678X, Vol. 342, article id 108778Article in journal (Refereed) Published
Abstract [en]
Background: Inference from fMRI data faces the challenge that the hemodynamic system that relates neural activity to the observed BOLD fMRI signal is unknown.
New method: We propose a new Bayesian model for task fMRI data with the following features: (i) joint estimation of brain activity and the underlying hemodynamics, (ii) the hemodynamics is modeled non-parametrically with a Gaussian process (GP) prior guided by physiological information and (iii) the predicted BOLD is not necessarily generated by a linear time-invariant (LTI) system. We place a GP prior directly on the predicted BOLD response, rather than on the hemodynamic response function as in previous literature. This allows us to incorporate physiological information via the GP prior mean in aflexible way, and simultaneously gives us the nonparametric flexibility of the GP.
Results: Results on simulated data show that the proposed model is able to discriminate between active and non-active voxels also when the GP prior deviates from the true hemodynamics. Our modelfinds time varying dynamics when applied to real fMRI data.
Comparison with existing method(s): The proposed model is better at detecting activity in simulated data than standard models, without inflating the false positive rate. When applied to real fMRI data, our GP model in several cases finds brain activity where previously proposed LTI models does not.
Conclusions: We have proposed a new non-linear model for the hemodynamics in task fMRI, that is able to detect active voxels, and gives the opportunity to ask new kinds of questions related to hemodynamics.
Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Bayesian inference, MCMC, fMRI, Hemodynamics, Gaussian processes, Misspecification
National Category
Probability Theory and Statistics Medical Imaging
Identifiers
urn:nbn:se:liu:diva-167230 (URN)10.1016/j.jneumeth.2020.108778 (DOI)000548505700004 ()
Funder
Swedish Research Council, 20135229
Note
Funding agencies: Swedish Research Council (Vetenskapsradet)Swedish Research Council [2013-5229]; Center for Industrial Information Technology (CENIIT) at Linkoping University
2020-06-292020-06-292025-02-09