Brain Connectivity and Visual Representation

Background: After a stroke, the balance between the two halves of the brain can be lost. This may cause people to lose the ability to perceive a side of space. This is called neglect. Having people wear prism glasses (called PA) can reduce neglect symptoms. Researchers want to find out more about how PA, and whether it restores the balance in the brain. Objective: To learn how prism adaption temporarily changes vision and connections in the brain. Eligibility: People ages 18 75 with brain damage of the right side of the brain from a stroke or other cause, leading to neglect. Healthy volunteers ages 18 75. Design: Participants will have 1 3 visits. Participants will be screened with a neurological exam. They may also have: Tests of thinking and vision Tests to see which eye and hand they prefer A pregnancy test All participants will: Answer questions about their personality, style of thinking, and beliefs. Do simple tasks on paper or computer Have magnetic resonance imaging. They will lie on a table that can slide in and out of a cylinder in a strong magnetic field. Participants will lie still or do computer tasks in the scanner. Participants may also have: Transcranial magnetic stimulation. A brief electrical current passes through a wire coil on the scalp. This creates a magnetic pulse that affects brain activity. Participants may be asked to tense certain muscles or perform simple actions or tasks. PA. They will sit in front of a board and point to a dot on it while they wear prism glasses that shift vision to the left or right.