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March 2008 False discovery rate analysis of brain diffusion direction maps
Armin Schwartzman, Robert F. Dougherty, Jonathan E. Taylor
Ann. Appl. Stat. 2(1): 153-175 (March 2008). DOI: 10.1214/07-AOAS133


Diffusion tensor imaging (DTI) is a novel modality of magnetic resonance imaging that allows noninvasive mapping of the brain’s white matter. A particular map derived from DTI measurements is a map of water principal diffusion directions, which are proxies for neural fiber directions. We consider a study in which diffusion direction maps were acquired for two groups of subjects. The objective of the analysis is to find regions of the brain in which the corresponding diffusion directions differ between the groups. This is attained by first computing a test statistic for the difference in direction at every brain location using a Watson model for directional data. Interesting locations are subsequently selected with control of the false discovery rate. More accurate modeling of the null distribution is obtained using an empirical null density based on the empirical distribution of the test statistics across the brain. Further, substantial improvements in power are achieved by local spatial averaging of the test statistic map. Although the focus is on one particular study and imaging technology, the proposed inference methods can be applied to other large scale simultaneous hypothesis testing problems with a continuous underlying spatial structure.


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Armin Schwartzman. Robert F. Dougherty. Jonathan E. Taylor. "False discovery rate analysis of brain diffusion direction maps." Ann. Appl. Stat. 2 (1) 153 - 175, March 2008.


Published: March 2008
First available in Project Euclid: 24 March 2008

zbMATH: 1137.62033
MathSciNet: MR2415598
Digital Object Identifier: 10.1214/07-AOAS133

Keywords: Diffusion tensor imaging , directional statistics , empirical null , multiple testing , spatial smoothing

Rights: Copyright © 2008 Institute of Mathematical Statistics

Vol.2 • No. 1 • March 2008
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