… ensemble of neurons that encoded the memory (called an “engram) and engineered them to be controllable with flashes … called “optogenetics”). Then, when they reactivated the engram of that context while presenting a reward, the cells … The researchers also did the opposite, swapping an engram’s positive association for a fearful one. A year later …
… they could pinpoint the ensemble of a hippocampal “engram,” the neurons that encoded a specific fear memory. How … created a false memory by artificially reactivating the engram of a previously experienced place while giving the … conditioning fear. But then, when they reactivated the engram of that context while presenting a reward, the cells …