Neural Correlates of Observation of Tactile Stimulation in Healthy Subjects

This study will examine activity in the brain during the observation of touch. Studies with animals have shown that mirror neurons, or nerve cells, are active during the observation and performance of an action. The researchers for this study hypothesize that a similar system pertains to observing and experiencing touch. Patients ages 18 to 75 years old who are in good health, are right handed, and who are able to perform simple tasks that require attention may be eligible for this study. Pregnant women are not eligible. Patients who have not had a health screening at NIH will undergo a clinical and neurological exam. Women of childbearing potential will also have a pregnancy test. The screening will take about 2 to 3 hours. A diagnostic magnetic resonance imaging (MRI) scan will be performed if patients have not undergone one in the previous 12 months. During the procedure, patients will lie still on a table that will slide into the enclosed tunnel of the scanner. They will be asked to lie as still as possible for up to a few minutes at a time. As the scanner takes pictures, patients will hear knocking or beeping sounds, and they will wear earplugs to reduce the noise. Patients will be able to communicate with the MRI staff at all times during the scan, and they may ask to be moved out of the machine at any time. This scan will take about 2 hours. Two sessions are involved in the study. The first one is intended to familiarize patients with the procedure. During it, they will learn about hand stimulus, through watching a video showing the index finger of a hand being touched by a stick repeatedly. Then the activity will be repeated, but this time, a researcher will also touch the patient's index finger while he or she is watching the video. This session will take about 1 hour. The second session consists of a functional MRI scan, or fMRI. During it, pictures of the brain will be taken while patients perform tasks. All tasks will be explained in advance, and pat