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Computational and Mathematical Methods in Medicine
Volume 2014 (2014), Article ID 579652, 8 pages
http://dx.doi.org/10.1155/2014/579652
Research Article

Independent Component Analysis of Instantaneous Power-Based fMRI

1School of Psychology, Nanjing Normal University, Nanjing 210097, China
2Department of Medical Imaging, Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
3Departments of Psychiatry and Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA

Received 20 December 2013; Accepted 30 January 2014; Published 6 March 2014

Academic Editor: Rong Chen

Copyright © 2014 Yuan Zhong et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In functional magnetic resonance imaging (fMRI) studies using spatial independent component analysis (sICA) method, a model of “latent variables” is often employed, which is based on the assumption that fMRI data are linear mixtures of statistically independent signals. However, actual fMRI signals are nonlinear and do not automatically meet with the requirement of sICA. To provide a better solution to this problem, we proposed a novel approach termed instantaneous power based fMRI (ip-fMRI) for regularization of fMRI data. Given that the instantaneous power of fMRI signals is a scalar value, it should be a linear mixture that naturally satisfies the “latent variables” model. Based on our simulated data, the curves of accuracy and resulting receiver-operating characteristic curves indicate that the proposed approach is superior to the traditional fMRI in terms of accuracy and specificity by using sICA. Experimental results from human subjects have shown that spatial components of a hand movement task-induced activation reveal a brain network more specific to motor function by ip-fMRI than that by the traditional fMRI. We conclude that ICA decomposition of ip-fMRI may be used to localize energy signal changes in the brain and may have a potential to be applied to detection of brain activity.