We will examine brain development in unrelated healthy volunteers and siblings of our COS probands by combining resting- and task-related magnetic resonance imaging (MRI) and magnetoencephalography (MEG) imaging. Imaging studies may lead to greater understanding of the course, mechanisms, and influences on brain development of high-risk siblings and may lead to improved understanding of the risk factors, early identification, and optimization of brain maturation. For more than 20 years, imaging has been done under a separate protocol (89-M-0006); however, we now plan to incorporate these imaging studies into this protocol (as well as into our main patient screening and follow-up protocol (03-M-0035) by previously submitted amendment).