Wavelet-based multifractal analysis of fMRI time series

Shimizu, Yu, Barth, Markus, Windischberger, Christian, Moser, Ewald and Thurner, Stefan (2004) Wavelet-based multifractal analysis of fMRI time series. NeuroImage, 22 3: 1195-1202. doi:10.1016/j.neuroimage.2004.03.007


Author Shimizu, Yu
Barth, Markus
Windischberger, Christian
Moser, Ewald
Thurner, Stefan
Title Wavelet-based multifractal analysis of fMRI time series
Journal name NeuroImage   Check publisher's open access policy
ISSN 1053-8119
1095-9572
Publication date 2004-07
Sub-type Article (original research)
DOI 10.1016/j.neuroimage.2004.03.007
Open Access Status Not yet assessed
Volume 22
Issue 3
Start page 1195
End page 1202
Total pages 8
Place of publication Amsterdam, Netherlands
Publisher Elsevier BV
Language eng
Abstract Functional magnetic resonance imaging (fMRI) time series are investigated with a multifractal method based on the Wavelet Modulus Maxima (WTMM) method to extract local singularity ("fractal") exponents. The spectrum of singularity exponents of each fMRI time series is quantified by spectral characteristics including its maximum and the corresponding dimension. We found that the range of Hölder exponents in voxels with activation is close to 1, whereas exponents are close to 0.5 in white matter voxels without activation. The maximum dimension decreases going from white matter to gray matter, and is lower still for activated time series. The full-width-at-half-maximum of the spectra is higher in activated areas. The proposed method becomes particularly effective when combining these spectral characteristics into a single parameter. Using these multifractal parameters, it is possible to identify activated areas in the human brain in both hybrid and in vivo fMRI data sets without knowledge of the stimulation paradigm applied.
Keyword BOLD
Exploratory analysis
FMRI
Multifractals
Time series
Wavelet analysis
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Centre for Advanced Imaging Publications
 
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