Cover legend: The background is an immunohistochemical stain of cells expressing β-galactosidase (red) under the control of a κB promoter and medium spiny neurons (MSNs) expressing green fluorescent protein under control of dopamine D2 receptor (blue) in the nucleus accumbens (NAc) shell. In the foreground are 3-D reconstructions of Lucifer yellow-filled NAc MSNs artistically rendered by the authors. For more information, see the article by Christoffel et al. in this issue (pages 314–321).