Have you ever had the feeling that the place you are in for the first time, strikingly familiar to you?Or that this particular conversation in all its detail was already happening before?

This feeling called the French deja vu (literally translated as "already seen") and it is familiar to 60-80% of all people.

Although this is a rare phenomenon will not name, science knows about it, not so much. Its origin is unpredictable, it lasts for a moment and any traces that might register, does not leave after themselves. Only unsubstantiated affirmation: "I just had a deja vu!"

Today there are several theories about its origin. Here are the most significant:

Neural discharges

Unexpected deja vu means that learning experienced by almost impossible, so the scientists have to rely on the words of people who have experienced this condition.

However, it turned out that people with epilepsy in the beginning of the attacks of the disease is also quite often experience deja vu. This discovery made it possible to study this phenomenon in more detail.

Epileptic seizures are caused by a change in the electrical activity of neurons in the focal areas of the brain. This neural activity can spread like a shock wave in the earthquake throughout the brain, including the middle temple, which plays a key role in long-term storage of memories. From this before the epileptic fit and there is a deja vu.

To determine the departments, which are signals of deja vu, the researchers measured the neural activity of the brain in such patients. This Department was olfactory cortex. As a result there was an assumption that deja vu is the result of a dysfunctional electrical discharges in the brain.

Such neural discharges can occur in people with epilepsy. An example is the involuntary wince sometimes when falling asleep.

However, some researchers believe that deja vu epilepsy patients and healthy people of different phenomena, and indicate that at first it can last for a long time, the second is always fleeting.

The fault memory

Deja vu in healthy people may be the result of a failure of memory, which is divided into short and long term. Deja vu happens, according to some scholars, due to the difference in memory systems that handle new experience. Information can somehow escape the short-term memory and to get directly in "daddy" in the brain, where be stored long-term. This explains that a new event or phenomenon seems very familiar, but not so much "material", as this memory.

Reaction to the familiar details

Another theory is that deja vu may be a reaction systems memory brain familiar details of a completely new experience. For example, when you are in a foreign country you go to a restaurant with details in the interior, similar to the design of the restaurant in your hometown.

And of course, there are many paranormal theories - past lives, alien abduction or cautionary vision etc.

While this is only theory, but science does not stand still and sooner or later this mystery, like many others, which makes us our gray matter will be solved.