The dentate gyrus (DG) is a part of the hippocampus that plays a key role in forming new memories. It receives information from many areas of the brain, transforms them into new patterns, and sends them to another part of the hippocampus. How the different cell types within the hippocampus communicate with each other is poorly understood. Pablo Castillo, M.D., Ph.D., has received a 5-year, $2.6 million grant to identify the properties of key hippocampal neurons—most notably granule cells and hilar mossy cells—that interact to create an excitatory circuit known to be involved in learning and epilepsy. Findings may shed light on information processing and memory encoding and reveal how dysregulation of this circuit may contribute to brain disease including epilepsy, anxiety, schizophrenia, and depression. Dr. Castillo is a professor in the Dominick P. Purpura Department of Neuroscience and of psychiatry and behavioral sciences, and the Harold and Muriel Block Chair in Neuroscience at Einstein. (1R01NS113600)