title: DWT-CEM: an algorithm for scale-temporal clustering in fMRI.
abstract: The number of studies using functional magnetic resonance imaging (fMRI) has grown very rapidly since the first description of the technique in the early 1990s. Most published studies have utilized data analysis methods based on voxel-wise application of general linear models (GLM). On the other hand, temporal clustering analysis (TCA) focuses on the identification of relationships between cortical areas by measuring temporal common properties. In its most general form, TCA is sensitive to the low signal-to-noise ratio of BOLD and is dependent on subjective choices of filtering parameters. In this paper, we introduce a method for wavelet-based clustering of time-series data and show that it may be useful in data sets with low signal-to-noise ratios, allowing the automatic selection of the optimum number of clusters. We also provide examples of the technique applied to simulated and real fMRI datasets.
authors.affiliation: Institute of Mathematics and Statistics, University of São Paulo, Rua do Matão, 1010, Cidade Universitria, CEP 05508-090, São Paulo, S.P., Brazil. jsato@ime.usp.br
authors.forename: João Ricardo
authors.initials: JR
authors.lastname: Sato
authors.forename: André
authors.initials: A
authors.lastname: Fujita
authors.forename: Edson
authors.initials: E
authors.lastname: Amaro
authors.forename: Janaina Mourão
authors.initials: JM
authors.lastname: Miranda
authors.forename: Pedro Alberto
authors.initials: PA
authors.lastname: Morettin
authors.forename: Michal John
authors.initials: MJ
authors.lastname: Brammer
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000465:Algorithms; D001921:Brain / Q000098:blood supply / Q000502:physiology; D001931:Brain Mapping; D016000:Cluster Analysis; D004644:Emotions / Q000502:physiology; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D010775:Photic Stimulation / Q000379:methods; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors