Spatial wavelets for temporally correlated FMRI

Within the context of a properly formulated spatio-temporal model for functional magnetic resonance imaging (fMRI), we develop a procedure for wavelet-based activation estimation that explicitly accounts for the temporally correlated ´brain´ noise. This leads to a kind of resolution level - dependent wavelet thresholding, a novelty in the spatial setting. The method is illustrated on a visual A-B fMRI experiment and is seen to give significantly better results compared with those obtainable via a more conventional smoothing step involving preprocessing with a spatially homogeneous filter.