Brain-behavior correlations were studied using a new method called item-wise correlation, which is more powerful than traditional mean-wise correlation. The new method tests small correlations from individual trials against zero, leading to more significant results. Simulations and an fMRI study on math problem-solving showed that item-wise correlation found more significant brain-behavior links than mean-wise correlation. The new method also showed greater stability in trial order comparisons. Overall, the item-wise correlation approach is more effective for analyzing brain activity related to behavior in neuroimaging studies.