1. Departments of Neuroscience (M.G.O., S.K.M.), Houston, Texas 77030
2. Center on Addiction, Learning, and Memory (S.K.M., M.G.O., A.R.), Baylor College of Medicine, Houston, Texas 77030
3. Molecular and Cellular Biology (W.P., A.R., S.K.M.), Houston, Texas 77030
4. Department of Basic Medical Sciences (C.D.F., A.K., L.H., R.J.H.), University of Arizona College of Medicine, Phoenix, Arizona 85004