[Molecular and Neuronal Mechanisms of Forgetting]

Animals sense several types of information in their environments and some of those information are stored as memories. The retention of these memories must be regulated for the animals to survive continuously changing environments. However, the mechanisms underlying memory forgetting remain to be understood, partly because psychological studies have suggested that forgetting is a passive process. Recent behavioral genetic studies, using model animals, including mice, Drosophila and Caenorhabditis elegans, have revealed that forgetting is actively regulated in neuronal circuits. In particular, "forgetting cells" non-cell-autonomously accelerate forgetting in other neurons. In this review, we describe recent studies of the mechanisms of forgetting in model animals.