This study will evaluate new magnetic resonance imaging (MRI ) methods using a MRI machine more powerful than those in most hospitals. MRI is a diagnostic tool that uses a large magnet and radio waves to produce images of the human body. It can also provide information about brain chemistry and physiology. This study will use the new MRI hardware and methods to measure blood flow and metabolism in regions of the brain during simple tasks, such as listening to tones or watching flashing checkerboards.