In the article “Differential Regulation of AMPA Receptor and GABA Receptor Trafficking by Tumor Necrosis Factor-α,” by David Stellwagen, Eric C. Beattie, Jae Y. Seo, and Robert C. Malenka, which appeared on pages 3219-3228 of the March 23, 2005 issue, the concentration of TNFα given throughout the paper (60 nm) is incorrect. The correct concentration was 100 ng/ml (2 nm), except for slice experiments, for which the concentration was 1 μg/ml (20 nm). These corrections do not affect the conclusions of the paper.