Perception, Sensation, Cognition and Action in Humans

Background: When people see and hear, the brain changes signals from the eyes and ears into perceptions and thoughts. No one fully understands how this happens. Researchers want to explore how healthy brains process sights and sounds. Objectives: To explore how people understand what they see and hear when the brain processes sights and sounds. Eligibility: Participants aged 13-65 who have at least 20/40 vision in at least one eye and do not use a hearing aid. Design: Some participants will take tests online anonymously. They will do computer tasks related to colors and behavior. In-person participants will be screened with medical history and physical exam. They will complete questionnaires and vision and hearing tests. Off-site participants will be screened with questionnaires about themselves and their vision. If results indicate abnormal color vision, these off-site participants may be asked to provide saliva samples for genetic screening. In-person participants will plan how many testing sessions they will have and when. Sessions last 2-5 hours. They may include: * Magnetic Resonance Imaging: Magnets and radio waves to take pictures of the brain. Participants will lie on a table that slides in and out of a tube. They will do a task during the scan. * Magnetoencephalography: Records magnetic field changes from brain activity. Participants will sit or lie down. A cone will be lowered onto their head. They may do a task during the test. * Electromyography: Electrodes attached to the skin will measure the electrical activity of muscles. * Electroencephalogram: Electrodes on the scalp will record brain waves. * Electrocardiography: Electrodes on the chest will record heart electrical activity. * Tests of memory, attention, thinking, vision, and hearing. * Eye Tracking: Cameras will follow participants eye movements. They may wear a cap with infrared cameras in front of their eyes. During the sessions, participants vital signs may be monitored.