It's something most human beings on earth have experienced at some time or another that strange feeling of nostalgia we call 'deja-vu'. Literally French for 'already seen', it refers to when a person experiences a feeling that they have seen, experienced, or been somewhere before, even when they are sure this isn't true.
Now, according to a report in the Massachusetts Institute of Technology News, neuroscientists at MIT's Picower Institute for Learning and Memory have identified a neuronal mechanism that can help explain the sensation. The implications are many, considering this could help doctors treat all kinds of memory-related disorders, especially those that often affect the elderly.
The report explains that this formation of memories of places and contexts in which episodes occur, engages a part of the brain called the hippocampus, sub-regions of which contribute to different aspects of memory and learning.
There are similar modules, or cues, involved in the feeling of déjà vu. If you happen to find a railway station familiar, for instance, it could be because of the modules ticket counters, wooden benches, food stalls that can usually be found at railway stations everywhere. These little things that make each place unique are quickly amplified, rendering them familiar.
The MIT report states that researchers believe a set of neurons fire to provide a sort of blueprint for any new space we encounter. The next time we see the same space, the same neurons fire. This ensures we don't have to relearn what is already familiar to us. But, if we enter a space that is similar, a new set of neurons that overlap the old ones is created, giving us the feeling of having seen it before.
For the elderly, memory plays 'tricks' when it becomes difficult to form unique memories for similar yet distinct places and experiences, leading to confusion.
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