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- Title
Estimating the population local wavelet spectrum with application to non-stationary functional magnetic resonance imaging time series.
- Authors
Gott, Aimee N.; Eckley, Idris A.; Aston, John A. D.
- Abstract
Functional magnetic resonance imaging (fMRI) is a dynamic four-dimensional imaging modality. However, in almost all fMRI analyses, the time series elements of this data are assumed to be second-order stationary. In this paper, we examine, using time series spectral methods, whether such stationary assumptions can be made and whether estimates of non-stationarity can be used to gain understanding into fMRI experiments. A non-stationary version of replicated stationary time series analysis is proposed that takes into account the replicated time series that are available from nearby voxels in a region of interest (ROI). These are used to investigate non-stationarities in both the ROI itself and the variations within the ROI. The proposed techniques are applied to simulated data and to an anxiety-inducing fMRI experiment.
- Publication
Statistics in Medicine, 2015, Vol 34, Issue 29, p3901
- ISSN
0277-6715
- Publication type
journal article
- DOI
10.1002/sim.6592