Peaks are only less likely to change with the threshold index (-1tindex)set to the same value as the data sub-brick index (-1dindex). Different data and threshold indices may have high values in the data with low values in the threshold sub-brick. Often a statistical result, like a t-stat, is used as the threshold sub-brick, and a beta-value is used as the data sub-brick. Again, the clusterize tool in the GUI is good for exploring the relationship among all these factors. Adjust the threshold slider and the overlay and threshold sub-bricks to see the differences interactively.
