Open AccessFast and precise independent component analysis for high field fMRI time series tailored using prior information on spatiotemporal structure
Author(s) -
Suzuki Kiyotaka,
Kiryu Tohru,
Nakada Tsutomu
Publication year - 2002
Publication title -
human brain mapping
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.005
H-Index - 191
eISSN - 1097-0193
pISSN - 1065-9471
DOI - 10.1002/hbm.1061
Subject(s) - independent component analysis , computer science , contrast (vision) , pattern recognition (psychology) , functional magnetic resonance imaging , artificial intelligence , component (thermodynamics) , function (biology) , time point , algorithm , neuroscience , philosophy , physics , aesthetics , evolutionary biology , biology , thermodynamics
Independent component analysis (ICA) has been shown as a promising tool for the analysis of functional magnetic resonance imaging (fMRI) time series. Each of these studies, however, used a general‐purpose algorithm for performing ICA and the computational efficiency and accuracy of elicited neuronal activations have not been discussed in much detail. We have previously proposed a direct search method for improving computational efficiency. The method, which is based on independent component‐cross correlation‐sequential epoch (ICS) analysis, utilizes a form of the fixed‐point ICA algorithm and considerably reduces the time required for extracting desired components. At the same time, it is shown that the accuracy of detecting physiologically meaningful components is much improved by tailoring the contrast function used in the algorithm. In this study, further improvement was made to this direct search method by integrating an optimal contrast function. Functional resolution of activation maps could be controlled with a suitable selection of the contrast function derived from prior knowledge of the spatial patterns of physiologically desired components. A simple skewness‐weighted contrast function was verified to extract sufficiently precise activation maps from the fMRI time series acquired using a 3.0 Tesla MRI system. Hum. Brain Mapping 15:54–66, 2001. © 2001 Wiley‐Liss, Inc.