MEMORY is one of the biggest enduring mysteries of modern neuroscience, and has perhaps been researched more intensively than any other aspect of brain function. The past few decades have yielded a great deal of knowledge about the cellular and molecular mechanisms of memory, and it is now widely believed that memories are formed as a result of biochemical changes which ultimately lead to the strengthening of connections between nerve cells.
It is, however, also clear that memories are not encoded at the level of single neurons. Instead, the memory trace is thought of as a flurry of electrical activity within a scattered population of cells. Yet, very little is known about how memories are encoded and retrieved by populations of cells. Using a new large-scale recording technique, researchers from the Medical College of Georgia have now directly observed, for the first time, the population-level activity associated with encoding and retrieval of memory traces.