In the article “A Novel Ca²⁺-Independent Signaling Pathway to Extracellular Signal-Regulated Protein Kinase by Coactivation of NMDA Receptors and Metabotropic Glutamate Receptor 5 in Neurons,” by Lu Yang, Limin Mao, Qingsong Tang, Shazia Samdani, Zhenguo Liu, and John Q. Wang, which appeared on pages 10846-10857 of the December 1, 2004 issue, links to on-line supplemental material were not incorporated. Supplemental Figure 1 pertains to the last sentence of the Discussion and is available on-line at http://www.jneurosci.org/cgi/content/full/24/48/10846/DC1.