Error in Figure Legend. In the article titled “The Neurobiology of Dopamine Signaling,” published in the May issue of the ARCHIVES (2004;61:641-644), the legend to Figure 2 included an error. The description for part B should have read as follows: When cyclin-dependent kinase 5 (CDK5) is activated (eg, following long-term cocaine administration), it phosphorylates DARPP-32 on threonine 75, turning it into an inhibitor of PKA and switching off the regulations depicted in A.