Cover legend: Fluorescent image of the dentate gyrus of triple mutant mice: ArpC3^f/f; SlickV-CreER;Loxstop-lox Rosa26 Tomato Fluorescent protein. Image shows the mosaic distribution within the same tissue of wild-type neurons (green) and knock-out neurons (blue) after tamoxifen treatment. Nuclei are labeled with DAPI (red). Disruption of the Arp2/3 complex by loss of the ArpC3 subunit leads to progressive loss of dendritic spines over time in vivo, which is associated with schizophrenia-like endophenotypes. Cover design by Il Hwan Kim. For more information, see the article by Kim et al. (pages 6081–6092).