Ghebreab, S.

Smeulders, A.W.M.

English

Natural sensory stimuli elicit complex brain responses that manifest in fMRI as widely distributed and overlapping clusters of hemodynamic responses. We propose a statistical signal processing method for finding synchronous hemodynamic activity that directly or transiently reflects information about the experimental condition. When applied to fMRI data, the method searches for voxels with activation patterns exhibiting high coherence and simultaneously high variance across brain scans. The crux of the method is functional principal component analysis (fPCA) of activation patterns stored in a twodimensional data matrix, with rows and columns representing voxels and scans, respectively. Without external information, fPCA is performed directly on this data matrix. Otherwise, the data matrix is first transformed to highlight a specific source of variation, enabling fully or partially supervised fPCA with a single parameter determining the degree of supervision. We evaluated our method on a public benchmark of fMRI scans of subjects viewing natural movies. Our method turns out to be very suitable for flexibly uncovering distributed and overlapping hemodynamic patterns that distinguish well between experimental conditions or cognitive states

International Migration, Integration and Social Cohesion online publications

Identifying distributed and overlapping clusters of hemodynamic synchrony in fMRI data sets

https://pure.uva.nl/ws/files/1023323/90250_paa2010.pdf

Identifying distributed and overlapping clusters of hemodynamic synchrony in fMRI data sets

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International Migration, Integration and Social Cohesion online publications