Neuroscience of déjà vu


Jun 7, 2007

MIT researchers report the identification of a mechanism in the brain that's tied to the experience of déjà vu, French for "seen already." The neuroscientists studied how subregions of the hippocampus--a part of the brain responsible for creating memories--contribute to our ability to differentiate between distinct places that are very similar. To conduct their study, the scientists observed the behavior of genetically-engineered mice in similar chambers, one with a floor that could shock them. (Yeeowch!) From the MIT News Office:

Researchers believe that a set of neurons called place cells fire to provide a sort of blueprint for any new space we encounter. The next time we see the space, those same neurons fire. Thus we know when we've been somewhere before and don't have to relearn our way around familiar turf. But if we enter a space very similar to one we have seen before, a new but overlapping set of neurons creates the blueprint. When there is enough overlap between the two sets, we experience an eerie feeling of déjà vu--a French phrase that literally means, "already seen.