Optogenetic stimulation of a hippocampal engram activates fear memory recall

Abstract

[...]activation of cells labelled in a context not associated with fear did not evoke freezing in mice that were previously fearconditioned in a different context, suggesting that light-induced fear memory recall is context-specific. Together, our findings indicate that activating a sparse but specific ensemble of hippocampal neurons that contribute to a memory engram is sufficient for the recall of that memory. [...]our experimental approach offers a general method of mapping cellular populations bearing memory engrams.