Effect of Reward on Learning in Motor Cortex

Background: * Magnetic resonance imaging (MRI) uses a strong magnetic field and radio waves to take pictures of the brain. Some MRI studies suggest that this technique reveals brain differences in patients with a nervous system illness when compared to adults without a nervous system illness. Objectives: * To study functional changes in the brain that may be observed in people without any nervous system illness. * To learn more about which areas of the brain are necessary to perform certain tasks, especially learning simple motor sequences and processing rewards. Eligibility: * Healthy volunteers between the ages of 18 and 50 who are right-handed and are native English speakers, and who have no medical conditions that would prevent them from undergoing magnetic imaging. * Volunteers must not have a history of neurological or psychiatric illnesses. * Female volunteers must not be pregnant. Design: * Volunteers will be asked to undergo different types of magnetic imaging, including functional magnetic resonance imaging (fMRI), magnetic resonance spectroscopy (MRS), and/or transcranial magnetic stimulation (TMS), while participating in either a slot machine simulation or a key sequence learning task. * Volunteers will participate in one of four possible experiments: * Experiment 1: MRS/TMS and slot machine (3 visits, 3.5 hours in total). * Experiment 2: MRS/TMS and key sequence (3 visits, 3.5 hours in total). * Experiment 3: fMRI and slot machine (2 visits, 3 hours in total). * Experiment 4: fMRI and key sequence (1 visit, 2 hours in total). * Experiment types: * Slot machine: A computer game like a slot machine, where the user presses a button to start the game and watches as the three barrels of the machine spin into place. * Key sequence: Pressing a series of buttons in response to visual cues. * Volunteers will also be asked to give a small blood sample for genetic testing. * Volunteers will be paid a small amount of money (approximately $50 $80) during the