You may be asked to take part in lab sessions during Visits 1, 2, and 6 to test your brain activity and attention span. You will be asked to watch slides and listen to a series of tones. The slides will include pictures of people, nature, and artwork. Slides showing nude people, medical procedures, and victims of car crashes will also be shown. You will be shown examples of these slides before beginning the procedure and given the opportunity to withdraw from the study.