In experiments with mice that have early-stage Alzheimer's disease, scientists at the Massachusetts Institute of Technology found memories are still stored in the brain but the condition prevents them from being accessed.
The scientists used a optogenetics, a technique that involves activating brain cells with light, in a proof-of-concept study showing missing memories may still exist in Alzheimer's patients' brains -- but scientists need a method to unlock them.
Researchers at MIT have previously identified cells in the brain that store specific memories, as well as how to manipulate the cells, called engrams, to plant false memories, activate existing memories or alter emotions linked to a memory.
The researchers have also found mice with retrograde amnesia had impaired recall, but their brains continued to form new memories, causing them to question whether memories in Alzheimer's patients really disappear.