Lay Abstract PI: Ramirez, Julio J. Proposal Number: IBN-9722829 Two areas of the brain that are very important for learning and memory are the hippocampus and the entorhinal cortex. When the hippocampus is deprived of its connections with the entorhinal cortex, for example as a result of injury to the brain, memory functions become impaired but recover within two weeks after the injury. After injury, remaining areas of the entorhinal cortex and other brain areas grow new connections to the hippocampus. This project examines how these new connections work together to mediate compensatory changes in the brain and to promote the recovery of memory functions. The project clarifies how different brain regions involved in learning and memory work together and how they interact following damage to compensate for that damage. In addition to these specific contributions, the project provides fundamental information about the capacity of brain structures to reorganize and how such reorganization leads to changes in function.