title: A unified statistical approach for determining significant signals in images of cerebral activation.
abstract: We present a unified statistical theory for assessing the significance of apparent signal observed in noisy difference images. The results are usable in a wide range of applications, including fMRI, but are discussed with particular reference to PET images which represent changes in cerebral blood flow elicited by a specific cognitive or sensorimotor task. Our main result is an estimate of the P-value for local maxima of Gaussian, t, chi(2) and F fields over search regions of any shape or size in any number of dimensions. This unifies the P-values for large search areas in 2-D (Friston et al. [1991]: J Cereb Blood Flow Metab 11:690-699) large search regions in 3-D (Worsley et al. [1992]: J Cereb Blood Flow Metab 12:900-918) and the usual uncorrected P-value at a single pixel or voxel.
authors.affiliation: Department of Mathematics and Statistics, McGill University, Montreal, Quebec, Canada H3A 2K6.
authors.forename: K J
authors.initials: KJ
authors.lastname: Worsley
authors.forename: S
authors.initials: S
authors.lastname: Marrett
authors.forename: P
authors.initials: P
authors.lastname: Neelin
authors.forename: A C
authors.initials: AC
authors.lastname: Vandal
authors.forename: K J
authors.initials: KJ
authors.lastname: Friston
authors.forename: A C
authors.initials: AC
authors.lastname: Evans