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Proceedings Paper

Variational Bayesian framework for estimating parameters of integrated E/MEG and fMRI model
Author(s): Abbas Babajani-Feremi; Susan Bowyer; John Moran; Kost Elisevich; Hamid Soltanian-Zadeh
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Paper Abstract

The integrated analysis of the Electroencephalography (EEG), Magnetoencephalography (MEG), and functional magnetic resonance imaging (fMRI) are instrumental for functional neuroimaging of the brain. A bottom-up integrated E/MEG and fMRI model based on physiology as well as a method for estimating its parameters are keys to the integrated analysis. We propose the variational Bayesian expectation maximization (VBEM) method to estimate parameters of our proposed integrated model. VBEM method iteratively optimizes a lower bound on the marginal likelihood. An iteration of the VBEM consists of two steps: a variational Bayesian expectation step implemented using the extended Kalman smoother (EKS) and the posterior probability of the parameters in the previous step, and a variational Bayesian maximization step to estimate the posterior distributions of the parameters. For a given external stimulus, a variety of multi-area models can be considered in which the number of areas and the configuration and strength of connections between the areas are different. The proposed VBEM method can be used to select an optimal model as well as estimate its parameters. The efficiency of the proposed VBEM method is illustrated using simulation and real datasets. The proposed VBEM method can be used to estimate parameters of other non-linear dynamical systems. This study proposes an effective method to integrate E/MEG and fMRI and plans to use these techniques in functional neuroimaging.

Paper Details

Date Published: 27 February 2009
PDF: 11 pages
Proc. SPIE 7262, Medical Imaging 2009: Biomedical Applications in Molecular, Structural, and Functional Imaging, 72621T (27 February 2009); doi: 10.1117/12.813840
Show Author Affiliations
Abbas Babajani-Feremi, Henry Ford Hospital (United States)
Susan Bowyer, Henry Ford Hospital (United States)
John Moran, Henry Ford Hospital (United States)
Kost Elisevich, Henry Ford Hospital (United States)
Hamid Soltanian-Zadeh, Henry Ford Hospital (United States)
Univ. of Tehran (Iran, Islamic Republic of)

Published in SPIE Proceedings Vol. 7262:
Medical Imaging 2009: Biomedical Applications in Molecular, Structural, and Functional Imaging
Xiaoping P. Hu; Anne V. Clough, Editor(s)

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