Erratum: In the May 1, 2000 issue, the title of the article by A. Dosemeci, T. S. Reese, J. Petersen , and J.-H. Tao-Cheng, which appeared on pages 3076–3084, contained a printer's error. The title should read, “A Novel Particulate Form of Ca2+/Calmodulin-Dependent Protein Kinase II in Neurons.”