Cover legend: A schematic illustration of Reelin expression in glutamatergic pyramidal neurons in layer II of the entorhinal cortex and their projections to the hippocampus, illustrated here by seahorses (Hippocampus sp.). Reelin is a neuromodulator that regulates a number of neuronal functions, including synaptic strength and plasticity, suggesting that Reelin produced in the entorhinal cortex may influence hippocampal plasticity. In humans with Alzheimer's disease as well as in transgenic mouse models of the disease, these neurons are lost and/or decrease expression of Reelin, indicating that decreased Reelin from the entorhinal cortex may contribute to hippocampal dysfunction in Alzheimer's disease. For more information, see the article by Chin et al. in this issue (pages 2727–2733). Artwork by Katherine Nagel.