Cover legend: Immunofluorescent labeling of a human cortical astrocyte with GFAP (dark blue). Neurons are labeled with MAP2 (orange), vasculature is labeled with laminin (green), and nuclei are labeled with DAPI (yellow). Image by Nancy Ann Oberheim and Takahiro Takano. See the article by Oberheim et al. in this issue (pages 3264–3276).