Memory engram storage and retrieval

- We review the history of research into putative memory storage mechanisms.
- We highlight recent advances catalyzed by memory engram labeling technology.
- We discuss the physiological properties of engram cells in memory consolidation.
- We describe a novel investigation into the nature of retrograde amnesia.
- We propose a differentiation between the mechanism of memory storage and retrieval.

A great deal of experimental investment is directed towards questions regarding the mechanisms of memory storage. Such studies have traditionally been restricted to investigation of the anatomical structures, physiological processes, and molecular pathways necessary for the capacity of memory storage, and have avoided the question of how individual memories are stored in the brain. Memory engram technology allows the labeling and subsequent manipulation of components of specific memory engrams in particular brain regions, and it has been established that cell ensembles labeled by this method are both sufficient and necessary for memory recall. Recent research has employed this technology to probe fundamental questions of memory consolidation, differentiating between mechanisms of memory retrieval and the true neurobiology of memory storage.