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Proceedings Paper

Analysis of event-related fMRI using nonlinear regression self-organizing map neural network
Author(s): Stephan G. Erberich; Manou Liebert; Klaus Willmes; Armin Thron; Walter Oberschelp
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Paper Abstract

Functional magnetic resonance imaging (fMRI) becomes a common method to study task induced brain activation. Using rapid Echo Planar Imaging (EPI) sequences one can obtain a higher MR-Signal under a task condition close by activated areas as a result of susceptibility changes in blood oxygenation (BOLD effect). Beside the commonly used blocked task designs, event- related paradigms gain more importance for activation of higher cognitive functions enabling more sophisticated and complex paradigms. For the analysis of event-related fMRI data one can use statistical tests, in example t-test used by SPM Software. The introduced analysis method based on an artificial neural network algorithm, a self-organizing map (SOM), is capable to distinguish between task related activation, deactivation and baseline patterns from the time series. This is achieved by temporal sorting and projection of all events from one condition into one combined hemodynamic response sampling for each voxel. These responses, having individual patterns can be separated by their pattern features and is done by training of the neural network. After training the SOM consists of a pattern-to-voxel mapping which is superimposed onto either an anatomical or EPI image of the subject for the task evaluation.

Paper Details

Date Published: 21 May 2001
PDF: 9 pages
Proc. SPIE 4321, Medical Imaging 2001: Physiology and Function from Multidimensional Images, (21 May 2001); doi: 10.1117/12.428153
Show Author Affiliations
Stephan G. Erberich, Univ. Hospital/Aachen Univ. of Technology (United States)
Manou Liebert, Univ. Hospital/Aachen Univ. of Technology (Germany)
Klaus Willmes, Univ. Hospital/Aachen Univ. of Technology (Germany)
Armin Thron, Univ. Hospital/Aachen Univ. of Technology (Germany)
Walter Oberschelp, Aachen Univ. of Technology (Germany)

Published in SPIE Proceedings Vol. 4321:
Medical Imaging 2001: Physiology and Function from Multidimensional Images
Chin-Tu Chen; Anne V. Clough, Editor(s)

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