Cover legend: A representation of the molecular interactions that underlie plasticity processes in hippocampal neurons, as unraveled by transcriptome analysis. The bottom half shows a word cloud (Wordle © 2009 Jonathan Feinberg) of genes downstream of four neuronal activity-regulated transcription factors (CREB, SRF, EGR1, and FOS); the upper half is a scanned microarray image. Both images are superimposed with the dendritic arbor of a cultured hippocampal neuron. For more information, see the article by Benito et al. in this issue (pages 18237–18250).