Interpretation of Event-Related fMRI Using Cluster Analysis

Event-related fMRI can access more complex experimental paradigms than traditional block designs. A new problem, however, becomes the data analysis, i.e., the generation of appropriate statistical models. For parametric paradigms where a set of parameters describing task and stimulus can be varied, the number of different conditions becomes large. Even if the combinatorics of contrasts between conditions is reduced by assumptions, the number of contrasts that potentially may contribute to the functional interpretation becomes huge.