The brain's glitchy misfire: why you feel you have lived this moment before
You are standing in a coffee shop when a sudden, eerie sensation strikes: you have been here before. This is déjà vu, a fleeting, false sense of familiarity that affects an estimated 97% of people. But what is actually happening inside your mind during this momentary glitch?
Translated from French as "already seen," déjà vu is a momentary disruption in how your brain processes reality. While it feels like a memory, neurologist Jean Khoury explains that it is actually a false sense of familiarity. It occurs when there is an incongruence between the feeling that a situation is familiar and the logical knowledge that it cannot be.
The mechanism behind this sensation is believed to be a functional miscommunication between two specific brain regions. Specifically, a misfire occurs between the temporal lobe, which is responsible for storing memories, and the hippocampus, which handles the intake of new information. When the hippocampus fails to interact correctly with its surroundings, the line between a new experience and an old memory becomes blurred, creating a phantom recollection.
While occasional episodes are common, especially among young adults, certain factors may increase susceptibility. Researchers have proposed over 40 different theories regarding this phenomenon. Some evidence suggests that high levels of education, frequent travel, or even remembering your dreams might make you more prone to these episodes. Additionally, physical states like fatigue, sleep deprivation, or high stress can disrupt the brain's recognition processes.
In some instances, the sensation is linked to specific medical conditions. For example, people prone to migraines may experience déjà vu during an aura or a migraine episode. More significant neurological issues, such as temporal lobe epilepsy or certain types of dementia like frontotemporal dementia, can cause persistent or seizure-related feelings of familiarity. In these cases, the brain's ability to process new information and recall actual memories is directly compromised.
Source: How Does Déjà Vu Work?
