For the study, participants will undergo an MRI scan. During the MRI scan, patients will lie still on a table that can slide in and out of a metal cylinder surrounded by a strong magnetic field. Scanning time varies from 20 minutes to 3 hours, with most scans between 45 and 90 minutes. Patients may be asked to lie still for up to 90 minutes at a time. As the scanner takes pictures, there will be loud knocking noises, and patients will wear headphones to muffle the sound. The headphones will also enable patients to hear their voice. The patient's head will be positioned with a coil of 25 to 30 cm diameter and supported by a headrest. A microphone will be placed about 2 cm from the patient's mouth for communication and collection of data. Also, an angled mirror will be attached to the head coil, so that the patient can look outside of the scanner. By way of a projection screen, the patient will receive a visual cue to vocalize, or use his or her voice.