Cover legend: Three-dimensional deconvolved fluorescence image of cultured hippocampal neurons in which cellular components involved in synaptic activity, activity-dependent transcription, and synaptic plasticity are labeled. The presynaptic protein synapsin I (green) and the dendritic microtubule-associated protein MAP2 (blue) are labeled with antibodies, ribosomes (red) are labeled with NeuroTrace Nissl stain, and nuclear DNA (yellow) is labeled with Hoechst dye. Synaptic activity regulates gene transcription via activity-sensitive transcription factors, including CaRF (calcium-response factor). For more information, see the article by McDowell et al. in this issue (pages 7453–7465). Photograph by Ronan Chereau.