The default mode network of brain function hypothesis has recently attracted more attention in the neuro-science community. In this study, we addressed a new data-driven method that based on temporal anti-correlation with the posterior cingulate cortex, one node of the default mode network, to localize the brain activation related to task and spontaneous epileptic discharges. The experimental results of real fMRI data analysis show not only the task-related activation region can be robustly recognized without any prior information on the functional activation paradigm, but also the epileptogenic zone in some patients with frequent interictal epileptiform discharges can be localized reliably using resting-state fMRI without EEG.