Spatiotemporal analysis of event-related fMRI data using partial least squares.
Partial least squares (PLS) has proven to be a important multivariate analytic tool for positron emission tomographic and, more recently, event-related potential (ERP) data. The application to ERP incorporates the ability to analyze space and time together, a feature that has obvious appeal for event-related functional magnetic resonance imaging (fMRI) data. This paper presents the extension of spatiotemporal PLS (ST-PLS) to fMRI, explaining the theoretical foundation and application to an fMRI study of auditory and visual perceptual memory. Analysis of activation effects with ST-PLS was compared with conventional univariate random effects analysis, showing general consensus for both methods, but several unique observations by ST-PLS, including enhanced statistical power. The application of ST-PLS for assessment of task-dependent brain-behavior relationships is also presented. Singular features of ST-PLS include (1) no assumptions about the shape of the hemodynamic response functions (HRFs); (2) robust statistical assessment at the image level through permutation tests; (3) protection against outlier influences at the voxel level through bootstrap resampling; (4) flexible analytic configurations that allow assessment of activation difference, brain-behavior relations, and functional connectivity. These features enable ST-PLS to act as an important complement to other multivariate and univariate approaches used in neuroimaging research.
Rotman Research Institute of Baycrest Centre, University of Toronto, 3560 Bathurst Street, Toronto, Ontario, Canada M6A 2E1. mcintosh@psych.utoronto.ca
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McIntosh
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WK
Chau
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Protzner
D000161:Acoustic Stimulation; D000328:Adult; D000465:Algorithms; D001307:Auditory Perception / Q000502:physiology; D002560:Cerebrovascular Circulation; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D016018:Least-Squares Analysis; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008568:Memory / Q000502:physiology; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D015203:Reproducibility of Results