Refers to various techniques, such as magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), and positron emission tomography (PET), that enable scientists to capture images of brain tissue and structure and to reveal what parts of the brain are associated with behaviors or activities. Structural brain imaging is concerned with identifying the anatomy of the brain and its changes with disease. Functional brain imaging is concerned with identifying the pattern of activity in the brain when people are at rest or when they are performing a task.