In this study, there are 3 study assessment visits to the Martinos Center facility in Charlestown in which volunteers will be asked questions about their daily experience. At all 3 study visits, investigators will also record magnetic field readings of the brain using a non-invasive imaging technique known as magnetoencephalography (MEG). MEG is a technique that measures the small electrical currents produced when cells in the brain are active. This activity is sometimes called "brain waves."