Subjects will be referred to the PI by the Yale Liver Center. If interested in participating, they will be contacted by a research assistant for an initial phone screening. If the subject passes the screening, an appointment will be made for a MRS and fMRI at the Yale Magnetic Resonance Research Center (MRRC). Subjects will be asked to abstain from their HE medication (e.g. lactulose and/or rifaximin) for 12 hours prior to their appointment. At their appointment for MRS/fMRI, they will receive two IVs, one for medication infusion and another for periodic blood draws during the MRS. Subjects will be blindly randomized to one of two groups: A or B. Group A will receive flumazenil (Romazicon) and Group B will receive placebo (saline). One week post-infusion, patients will crossover groups; those originally in Group A will crossover to Group B and those originally in Group B will crossover to Group A. Once ready, a priming dose bolus of 0.4 mg of either flumazenil or placebo will be administered intravenously (Minute 0). At this time the 1H-MRS scan will begin. Over the next 6 minutes, a drip infusion of flumazenil or placebo mixed with saline will be administered to the patient at a rate of 0.1 mg flumazenil or placebo per minute for a total of 7 doses during the scan. A baseline pharmacokinetics (PK) sample will be drawn, processed and frozen and the intravenous line used to draw the sample will remain in patient until all samples have been drawn. Seven additional PK samples (2-4 mL each) collected during and after the scan will be used to evaluate the level of flumazenil circulating throughout the bloodstream during the course of the infusion and during the washout period.