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Evaluating stationarity via change-point alternatives with applications to fMRI data
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Aston, John A. D. and Kirch, Claudia (2012) Evaluating stationarity via change-point alternatives with applications to fMRI data. The Annals of Applied Statistics, Volume 6 (Number 4). pp. 1906-1948. doi:10.1214/12-AOAS565 ISSN 1932-6157.
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Official URL: http://dx.doi.org/10.1214/12-AOAS565
Abstract
Functionalmagnetic resonance imaging (fMRI) is now a well-established technique for studying the brain. However, in many situations, such as when data are acquired in a resting state, it is difficult to know whether the data are truly stationary or if level shifts have occurred. To this end, change-point detection in sequences of functional data is examined where the functional observations are dependent and where the distributions of change-points from multiple subjects are required. Of particular interest is the case where the change-point is an epidemic change-a change occurs and then the observations return to baseline at a later time. The case where the covariance can be decomposed as a tensor product is considered with particular attention to the power analysis for detection. This is of interest in the application to fMRI, where the estimation of a full covariance structure for the three-dimensional image is not computationally feasible. Using the developed methods, a large study of resting state fMRI data is conducted to determine whether the subjects undertaking the resting scan have nonstationarities present in their time courses. It is found that a sizeable proportion of the subjects studied are not stationary. The change-point distribution for those subjects is empirically determined, as well as its theoretical properties examined.
Item Type: | Journal Article | ||||
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Divisions: | Faculty of Science, Engineering and Medicine > Science > Statistics | ||||
Journal or Publication Title: | The Annals of Applied Statistics | ||||
Publisher: | Institute of Mathematical Statistics | ||||
ISSN: | 1932-6157 | ||||
Official Date: | December 2012 | ||||
Dates: |
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Volume: | Volume 6 | ||||
Number: | Number 4 | ||||
Page Range: | pp. 1906-1948 | ||||
DOI: | 10.1214/12-AOAS565 | ||||
Status: | Peer Reviewed | ||||
Publication Status: | Published | ||||
Access rights to Published version: | Restricted or Subscription Access |
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