Cover legend: Pseudocolor image of an organotypic hippocampal slice showing glial cells loaded with the calcium-sensitive dye Calcium Orange (dentate gyrus at top right, CA3 at bottom, and CA1 at left). Calcium Orange was used to monitor astrocyte calcium responses to single-neuron stimulation. For more information, see the article by Bernardinelli et al. in this issue (pages 8905–8919).