Cover legend: This artistic rendering shows papaverine-induced ribosomal S6 phosphorylation in striatonigral and striatopallidal medium-sized spiny neurons. The original image showed triple-labeled nNOS-positive interneurons and phospho-rpS6 in Drd2-EGFP mice. Art and original image by Emma Puighermanal, Anne Biever, and Emmanuel Valjent. For more information, see the article by Biever et al. (pages 4113–4130).