Outcome measures: In a first phase, the outcome measure will be the behavioral response on a task that relies on the ACC. In a second phase, outcome measures will be the effects on MR measures. These will include task-related blood oxygen level-dependent (BOLD) responses, as well as resting state BOLD fMRI. Other MR measures, such as magnetic resonance spectroscopy (MRS) and arterial spin labeling (ASL), will also be explored as potential biomarkers.