Shelby Bradford in The Scientist:
Many people view forgetting as an inconvenience, and if it occurs extensively, they associate it with neurodegenerative diseases. However, some evidence suggests that nonpathological forgetting is an adaptive and active part of learning and memory maintenance.1 “The environment is changing, and to adapt to an environment that is constantly changing, we need to update our memories; and updating our memories also means forgetting,” said Livia Autore, a neuroscientist and postdoctoral researcher in the lab of Tomás Ryan at the Trinity College Dublin and author of a study published in Cell Reports.2 The findings indicate that forgetting is an active process that is important for the ability to remember and that it serves as a basis for understanding altered memory capacity.
The physical component of a memory consists of activated neurons and synapses formed during an event, collectively called an engram.3 To study changes in engram cells during forgetting, Autore’s team labeled neurons in the hippocampus with an adeno-associated virus cocktail that marked engrams formed during training experiences as well as all activated neurons during the testing phase. Autore’s group then set up an object context training experiment in which mice explored one set of objects, for instance, a pair of small water bottles, in a chamber with a pattern of triangles on the wall to provide contextual information. An hour later, the researchers exposed the mice to a different pair of objects, like small statues, in a different chamber with striped walls as interference.
More here.