Creating a False Memory in the Hippocampus

Can You Trust Your Memory? Being highly imaginative animals, humans constantly recall past experiences. These internally generated stimuli sometimes get associated with concurrent external stimuli, which can lead to the formation of false memories. Ramirez et al. (p. 387 ; see the cover) identified a population of cells in the dentate gyrus of the mouse hippocampus that encoded a particular context and were able to generate a false memory and study its neural and behavioral interactions with true memories. Optogenetic reactivation of memory engram–bearing cells was not only sufficient for the behavioral recall of that memory, but could also serve as a conditioned stimulus for the formation of an associative memory.