There are several hypotheses about what causes déjà vu. These range from the paranormal—past lives, alien abduction, and precognitive dreams—to memories generated from non-first-hand experiences. Now, researchers are in the process of exploring déjà vu and how the brain can sometimes short-circuit.
Have you ever had the strange sensation of being precisely where you’ve been previously, doing exactly what you swear you have done before? It might be while redecorating your home room, conversing, or simply sitting by yourself doing nothing, reports The Epoch Times.
If this is the case, you are not alone.
This sense of familiarity is known as déjà vu (a French term meaning “already seen”), and it is said to occur on an occasional basis in 60 to 80 percent of individuals. It is virtually usually a transient event that happens at random.
So, what is causing these sensations of familiarity?
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Despite popular culture coverage, feelings of déjà vu are rarely comprehended in scientific terms. Déjà vu occurs suddenly and unexpectedly, with no bodily indications other than the declaration: “I just had déjà vu!”
Many studies believe the phenomena is a memory-based experience and that it is caused by the brain’s memory centers.
The medial temporal lobes are critical for long-term memory retention of events and facts. Certain parts of the medial temporal lobes are critical in detecting familiarity or recognition, rather than detailed remembering of individual events.
It has been argued that detecting familiarity is dependent on rhinal cortex function, whereas comprehensive remembrance is associated with the hippocampus.
The unpredictability of déjà vu events in healthy individuals renders empirical research challenging. Any such study relies on self-reporting from those participating.
Glitches in the Matrix
When seizures start in the medial temporal lobe, a portion of epilepsy patients regularly experience déjà vu at the beginning of a seizure. This has provided researchers with a more regulated experimental method of researching déjà vu.
Changes in the electrical activity of neurons in certain brain areas trigger epileptic seizures. Similar to how earthquake shock waves propagate across the entire brain, this malfunctioning neural activity can do the same. The medial temporal lobes are one of the areas of the brain where this electrical stimulation may take place.
Prior to the epileptic occurrence, an electrical disturbance in this neural system produces an aura (kind of a warning) of déjà vu.
Scientists were able to locate the areas of the brain where déjà vu signals originate by analyzing neuronal discharges in the brains of these individuals.
Déjà vu is more easily generated in epileptic patients by electrical stimulation of the rhinal cortices rather than the hippocampus. These findings lead to the hypothesis that déjà vu is caused by a faulty electrical discharge in the brain.
These neuronal discharges can be seen in individuals who do not have epilepsy in a non-pathological manner. A hyponogogic jerk is one example of this, which is an involuntary twitch that can occur soon before falling asleep.
It has been claimed that déjà vu is caused by a similar neuronal release, culminating in an odd feeling of familiarity.
Some experts claim that the form of déjà vu experienced by patients with temporal lobe epilepsy differs from conventional déjà vu.
The déjà vu felt prior to an epileptic seizure may be persistent rather than transient, as it is in individuals who do not suffer epileptic seizures. The vivid recognition paired with the understanding that the surroundings is genuinely novel grounds the feeling of déjà vu in those who do not have epilepsy.
Mismatches and Short Circuits
In healthy participants, déjà vu is described as a memory malfunction that could reveal how the memory system is structured. According to some studies, déjà vu is caused by a disparity in memory systems that causes an incorrect formation of a detailed memory from a novel sensory experience.
In other words, information bypasses short-term memory and enters long-term memory instead.
This suggests that a discrepancy between sensory input and memory-recall output causes déjà vu. This explains why a novel encounter could seem familiar, yet not as concrete as a completely recalled memory.
Other ideas propose that activation of the rhinal neural system, which is involved in the detection of familiarity, occurs without activation of the hippocampus’s recollection system. This creates a sense of recognition without providing particular specifics.
In accordance with this theory, déjà vu is a response of the brain’s memory systems to a familiar experience. This is a novel experience, but it has numerous recognizable aspects, just in a somewhat different environment. What is an example? Being in a foreign pub or restaurant that has the exact layout as one you frequent at home.
There are even more hypotheses about what causes déjà vu. These range from the paranormal—past lives, alien abduction, and precognitive dreams—to memories generated from non-first-hand experiences (such as scenes in movies).
So far, there is no straightforward explanation for why déjà vu happens, but breakthroughs in neuroimaging techniques may help us comprehend memory and the tricks our minds perform on us.