In the article “Pigment-Dispersing Factor and GABA Synchronize Cells of the Isolated Circadian Clock of the Cockroach Leucophaea maderae,” by Nils-Lasse Schneider and Monika Stengl, which appeared on pages 5138-5147 of the May 25, 2005 issue, the DOI number given beneath the correspondence address is not correct as shown in the print version. The correct DOI number for this article is “DOI:10.1523/JNEUROSCI.5138-A-04.2005.”