Cover legend: Immunohistochemical labeling of parvalbumin-expressing inhibitory interneurons (yellow) and cell nuclei (DAPI, purple) in the somatosensory cortex of a postnatal day 15 Dp(16)1Yey/+ mouse (a mouse model of Down syndrome). Photoshop was used to adjust the hue and contrast of the image. For more information, see the article by Goodliffe, Olmos-Serrano et al. (pages 2926–2944).