ET

n functional magnetic resonance imaging (fMRI), the question of whether a region of the brain is being activat-ed with a stimulus is important. Typically, it is deter-mined whether individual voxels are active through a multiple regression and thresholding [1]–[3] with statements made about clusters of voxels. Standard individual voxel activation statistics are computed via multiple regression. The generally computed activation t-statistic maps are thresholded objectively with methods that account for the multiple comparisons problem such as Bonferroni adjust-ment for controlling the familywise error rate. Regions of interest (ROIs) are formed from the thresholded maps by using the AND in addition to the OR operation [4]. The voxels in the ROIs can be analyzed for joint activation. It is extremely important to determine appropriate thresholds t