At the time the article "Imaging Dopamine Transmission in Cocaine Dependence: Link Between Neurochemistry and Response to Treatment" by Diana Martinez, M.D., et al., was published online on March 15, 2011, the bar graphs in figure 2 were labeled incorrectly: the Responders and Nonresponders bars were flipped. The bars on the left for the nondisplaceable binding potential in the baseline condition and following methylphenidate actually represent the responders and the bars on the right represent the nonresponders. This change was made for the article's online posting on March 24, 2011, and for the article's print appearance in the June 2011 issue and for its online posting as part of that issue.