The most common design of a functional MRI (fMRI) experiment is a block des
ign. The use of rapid imaging, however, and carefully designed paradigms ma
kes the separation of cognitive events possible. Such experiments make use
of event-related paradigms, in which a task involving several cognitive pro
cesses is repeated. In analyzing data from such experiments, existing metho
ds often prove inadequate, because the prediction of the exact shape or tim
ing of the time course is difficult. Here we present an analysis of varianc
e (ANOVA) method for analyzing fMRI data that does not require any assumpti
ons about the shape of the activation time course. Consequently, this metho
d can simultaneously detect brain areas showing a variety of stimulus-locke
d time courses in the same experiment. The utility of this technique is dem
onstrated by the analysis of data from two event-related paradigms in which
regions of activation are detected that correspond to a variety of distinc
t neural processes, yielding significantly different temporal signal change
s. (C) 1999 Wiley-Liss, Inc.