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Fast joint detection-estimation of evoked brain activity in event-related fmri using a variational approach

Chaari, Lotfi and Vincent, Thomas and Forbes, Florence and Dojat, Michel and Ciuciu, Philippe Fast joint detection-estimation of evoked brain activity in event-related fmri using a variational approach. (2013) IEEE Transactions on Medical Imaging, 32 (5). 821-837. ISSN 0278-0062

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Official URL: http://dx.doi.org/10.1109/TMI.2012.2225636

Abstract

In standard within-subject analyses of event-related fMRI data, two steps are usually performed separately: detection of brain activity and estimation of the hemodynamic response. Because these two steps are inherently linked, we adopt the socalled region-based Joint Detection-Estimation (JDE) framework that addresses this joint issue using a multivariate inference for detection and estimation. JDE is built by making use of a regional bilinear generative model of the BOLD response and constraining the parameter estimation by physiological priors using temporal and spatial information in a Markovian model. In contrast to previous works that use Markov Chain Monte Carlo (MCMC) techniques to sample the resulting intractable posterior distribution, we recast the JDE into a missing data framework and derive a Variational Expectation-Maximization (VEM) algorithm for its inference. A variational approximation is used to approximate the Markovian model in the unsupervised spatially adaptive JDE inference, which allows automatic fine-tuning of spatial regularization parameters. It provides a new algorithm that exhibits interesting properties in terms of estimation error and computational cost compared to the previously used MCMC-based approach. Experiments on artificial and real data show that VEM-JDE is robust to model misspecification and provides computational gain while maintaining good performance in terms of activation detection and hemodynamic shape recovery.

Item Type:Article
Additional Information:Thanks to IEEE editor. The definitive version is available at http://ieeexplore.ieee.org The original PDF of the article can be found at IEEE Transactions on Medical Imaging website : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6335481
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Other partners > Institut polytechnique de Grenoble (FRANCE)
Other partners > Université Pierre Mendès France, Grenoble 2 - UPMF (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Université de Toulouse > Université Toulouse - Jean Jaurès - UT2J (FRANCE)
Université de Toulouse > Université Toulouse 1 Capitole - UT1 (FRANCE)
Other partners > Université Joseph Fourier Grenoble 1 - UJF (FRANCE)
Other partners > Université de Lorraine (FRANCE)
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Deposited By: IRIT IRIT
Deposited On:27 Feb 2015 10:39

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