IN BRIEFResearchers have discovered that memories form and get recalled along two distinct circuits in the brain. This could be relevant to the study of Alzheimer’s disease.WHERE MEMORIES FORMNew research suggests that the subiculum, a part of the hippocampus that is rarely studied, is central to the memory retrieval process. This work also indicates that memory formation and memory recall follow different neural circuits. According to the team of researchers, this work represents the first identification of this recall circuit in vertebrates, although scientists did identify a similar mechanism in Caenorhabditis elegans, a roundworm.The team used laboratory mice that they had genetically engineered and conditioned to react to changes in light so that a reaction to green light would be tied to the subiculum neurons, which could then be inhibited. They then manipulated memory formation and recall using fear-conditioning events so the mice would make associations that were more or less pleasant in specific situations.