Many of us know the feeling: You\’ll be going about your day, minding your own business, folding some laundrynothing out of the ordinary, when suddenly a sensation of familiarity washes over you, and you\’re completely aware that it\’s happening:
I\’ve been here before. P Except you haven\’t. P Or have you? You might try to think back and pinpoint when you\’d experienced this moment before. ButPjust as quickly as the feeling hits you, it\’s gone. Did you predict the future? Were you seeing something from a past life? PWhat isPdj vu, anyway? The phenomenon of dj vu (French for \”already seen\”) is, scientifically, pretty poorly understood, but there arePa few theories: Dj vu may be the result of some sort ofP\”mismatch\” in how we\’re simultaneously sensing and perceivingPthe world around us. Perhaps we something familiar, for example, and our mind is instantly transported to the first time we smelled it. (It\’s a vague theory, though, and doesn\’t explain why mostPdj vuPepisodes don\’t reflect true past events. ) Dj vu may be a fleeting malfunctioning between the long- and short-term circuits in the. ThePinformation our brain takes in about its surroundings may \”shortcut\” its way straight to long-term, bypassing typical storage transfer mechanisms, so when we have a moment of dj vu,Pit feels as though we\’re experiencing something from our distant past. P A region of the brain called theP rhinal cortex, involved in detecting familiarity, may be inexplicably activated without actually activating memory (hippocampal) circuits. That may explain whyPdj vu episodes feel so non-specific when we try to figure out where and when we had previously experienced a particular moment.
In fact, some patients with epilepsy reliably experiencePdj vu at the beginning of a seizure. For these individuals, Pof the rhinal cortexP and not so much the hippocampus itself inducesPdj vu. Dj vu isP Pin 60-70% of us, most commonly in those between the ages of 15 and 25. Why? We have no idea. Interestingly, though, Pyears ago out of my own curiosity on the matter, having experienced it fairly frequently. I\’m now 26, though, and can\’t remember the last time I had an episode. Are any of these theories correct? We may never know. After all, since episodes of dj vu are completely unexpectednot to mention, for most of us, extremely rarereal empirical research on the topic is next to impossible. What are your experiences withPdj vu? P Trapped in a time loop: That s how one man felt because of his recurring d j vu episodes. Unlike the vague, fleeting sensation most people experience in d j vu, his episodes were persistent and long. The 23-year-old British man started to have frightening episodes of shortly after starting college, said the researchers who detailed his unusual case in a new report. For minutes, and sometimes even longer, he would feel that he had already experienced all of those moments. The episodes grew in intensity and became debilitating. Rather than simply the unsettling feelings of familiarity which are normally associated with d j vu, he complained that it felt like he was actually retrieving previous experiences from memory, not just finding them familiar, the researchers said. [ Three years after the experiences began, the young man could no longer even watch TV or read the paper because he would have a disturbing feeling that he had encountered the content before, the researchers said.
The haunting sensation was stronger than just a feeling of familiarity. The man said he felt that at every present moment, he was reliving the past. What made the case even more peculiar was that the man didn t suffer from any of the neurological conditions previously reported in people who experience frequent d j vu episodes. Instead, he suffered from anxiety, suggesting that anxiety disorders could be more related to d j vu than previously thought, which was published Dec. 8 in the Journal of Medical Case Reports. D j vu in the brain Scientists have yet to find a complete explanation for d j vu, which is French for already seen, but a popular idea is that the false sensation of familiarity is the result of a failure in the brain s memory system, which resides in the temporal lobe of the brain. Most explanations of d j vu suggest that it s a phenomenon that arises from activity within the temporal lobe. Some kind of mistimed firing of neurons, perhaps a temporary glitch in our processing of incoming information, said Christine Wells, a psychologist at Sheffield Hallam University in the United Kingdom who co-authored the new report of the man s case. A key structure within the temporal lobe is the, which is heavily involved in memory, Wells said. We have every reason to believe that s the area that s involved in d j vu. In fact, although almost anyone can have an episode of d j vu every once in a while, more frequent and intense forms of the phenomenon are usually seen in people who have seizures in the temporal lobe, a condition called.
In this man s case, doctors looked for signs of seizures, but neurological examinations, including EEGs (electroencephalograms) and brain scans, didn t turn up anything. His brain activity, as far as doctors could measure, looked normal. And a set of psychological tests of his memory didn t reveal any major problem, either. Could it be anxiety? Although the researchers didn t find neurological clues that could explain this man s d j vu, it is still possible that there are signs they missed, Wells said. The available technologies may not be sophisticated enough to pick up on what could be very subtle differences in the brain, she said. The other explanation for the man s chronic d j vu is his. A lot of the previous research has focused quite rightly on temporal lobe epilepsy, Wells said. But it is possible that there are other disorders, such as anxiety disorders, in which people experience d j vu slightly more often than normal. The young man s anxiety was so severe that he had to take a short break from college, and that s when his d j vu episodes began. These episodes caused him even more anxiety and distress, possibly creating a vicious circle, the researchers said. At one point, the d j vu became fairly continuous this happened right after the man took the hallucinogenic drug lysergic acid diethylamide (LSD), he told the researchers. Still, the case of a single man cannot prove that there s a link between anxiety and d j vu, the researchers said. But the case raises the question, and should be studied further, they said. Email. Follow Live Science,. Originally published on.