Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
Cocaine induces c-fos immunoreactivity (red) in nuclei of medium spiny neurons of the striatum. Mu opiod receptor immunoreactivity (green) indicates neurons belonging to the direct output pathway. Courtesy of Drs. Amy Ramsey and Michel Cyr, Duke University Medical Center, NC.