Do you get déjà vu? Memory problems make time feel repeated

Summary: Déjà Vu, the spooky feeling that a new moment has happened before, has perplexed scientists and philosophers for centuries. Neuroscientific now believe that it is a normal brain failure linked to how memory and perception interact.

Studies show that short electrical discharges in the temporal lobe and the hippocampus can evoke this sensation, similar to what happens in mild epilepsy. Psychologists also link Déjà vu with the unconscious processing of family patterns, where the brain note details that we do not register consciously, creating a false sense of familiarity.

Key facts:

Memory mixture: Déjà Vu probably arises when the brain marks by mistake a new experience as a family due to overlapping memory circuits.

Source: University of Melbourne

Do you ever have that peculiar feeling that what you are doing or seeing has already happened, even when you are quite sure you have not done it?

That abrupt and sharp sense of familiarity, although unlikely, is a phenomenon known as Déjà Vu, the French phrase for “already seen.”

Déjà Vu feels so strange and amazing that popular culture has associated it with everything, from time trips to failures in “The Matrix”.

But Déjà Vu is not a sign that can be seen in his past life or traveling to an alternative dimension, it is part of how the brain works, says Professor Sam Berkovic, clinical neurologist and director of the Epilepsy Research Center in Austin Health.

“It is a normal phenomenon. And when you ask people, around 60 to 70 percent will say they understand it,” he says. “I understand from time to time. You shake your head and say: ‘Oh, it’s my brain playing tricks about me,’ which is exactly what it is.”

The ephemeral nature of Déjà vu makes it difficult to study, so scientists are not exactly sure of what causes it. Some researchers attribute it to discrepancies or errors in parts of the brain that control memory.

Professor Berkovic says that researchers have learned a lot about how the brain works when studying patients who have epileptic seizures, which occur when there is an abnormal electric shock in part of the brain.

People with epilepsy can sometimes experience a high and extreme sensation of Déjà Vu at the beginning of a seizure. This is often an indication of a discharge in the hippocampus, a deep structure in the temporal lobe and the part of the brain under the temples that memory controls.

But the déjà vu experienced by a person with epilepsy is longer and more intense than the so -called physiological vu, or the daily déjà vu in people without epilepsy.

“It’s all that covers it. They are absolutely convinced that they are experiencing something that has happened before,” says Professor Berkovic.

Scientists have stimulated that part of the brain in patients with epilepsy to replicate those intense feelings of Déjà vu.

“We really don’t know why it happens in healthy people because we have never caught electrodes in the brain of healthy people,” he adds. “But it could be that similar downloads can evoke the same feelings.”

Professor Berkovic says that Déjà Vu is considered so normal that when he and his doctoral student, Dr. Piero Perucca, studied relatives of people with a slight form of epilepsy, discovered that they experienced a greater frequency of intense déjà vu that could be considered epileptic.

These relatives never thought they complained with their doctors about it because they did not believe it was abnormal.

The Associate Professor Piers Howe, at the Melbourne School of Psychological Sciences, links Déjà Vu with the feeling of having a “sixth sense.”

“These are quite defined terms, and they are not scientific, but many people use them to mean that they feel something that happens, although they cannot see or describe it,” he says.

Professor Howe decided to look closely at this confusing feeling when a student approached her with a strange experience that she described as a sixth sense. The student had recently met a friend who had not seen in a long time, and thought he had immediately had a car accident.

“He had recovered completely, and there was no visible track, but my student knew he had an accident. And she was right,” says Professor Howe. “She thought she had a mystical property and wanted me to confirm it.”

Fleeting memories or sensations can be difficult to replicate in a laboratory. But Professor Howe and her student Margaret Webb thought they could imitate the mystical experience of this student showing similar photographs of the same person.

Each photograph would show that the subject looks slightly different, be it a new pair of earrings or a different lipstick.

“The participants should indicate if they thought a change had occurred and what it was,” says Professor Howe.

“What we found is that people were really very good to identify changes that could not locate or describe.

“They would say: ‘I know something has changed, I just don’t know what it is.”

It is likely, then, that the student who had claimed to make a sixth meaning had unconsciously noticed subtle information about her friend who led her to believe, correctly, that she had had a car accident.

Professor Howe has performed a series of similar experiments, all of whom indicated that when people look at something, they process much more information than they think they do. It is possible that they have been aware of only two or three characteristics of someone’s face, but their brain has noticed much more.

The same type of process can be happening when someone experiences Déjà Vu. Something that you see or listening may have caused a mysterious feeling of familiarity; You just can’t identify where memory comes from.

“Our visual memory is not based only on memorizing two or three objects in a scene, it is also collecting the summative statistics of the rest of the scene,” says Professor Howe.

“What people could claim as Déjà vu or a sixth sense is what you have collected from one of your senses. You just don’t know what you have.

“That information comes to you as a feeling that something has happened or will happen.”

Professor Howe says that his findings are closely related to studies on Déjà Vu that have tried to cause false memories in people by showing them a list of related words, such as door, panel and glass.

Later, when participants are shown a word related to the words they have studied, for example, the word “window” seems familiar to create (incorrectly) that they have seen it before.

As in the experiments carried out by Professor Howe, this form of Déjà Vu is caused by the brain that collects more information than the person is aware. The feeling of familiarity is caused by the brain that subconsciously determines that the word “window” is semantically related to the words on the list.

Akira O’Connor, a professor of psychology at the University of St Andrews in the United Kingdom, conducted such a study in 2016. Then she used magnetic resonance scans to see what was happening in the brains of the participants.

He discovered that the experience Déjà Vu activated the front regions of the brain responsible for the memory conflict, or reviewing our memories. He concluded that Déjà Vu could be the result of the brain trying to solve an error between what you think you have seen before and what you are really seeing.

Then, the next time he feels that he is on a marmot day of real life, remember that his brain is normally behaving.

“The brain is very complex,” says Professor Berkovic. “And Déjà Vu is your brain that behaves in its very complicated way.”

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Author: Kate Stanton
Source: University of Melbourne
Contact: Kate Stanton – University of Melbourne
Image: The image is accredited to Neuroscience News