The exact reason why the human brain experiences déjà vu is not fully understood, but there are a few theories.

One theory is that déjà vu is caused by a temporary glitch in the brain’s memory system. This glitch can cause the brain to mistakenly believe that a current experience is a memory of a previous experience.

Another theory is that déjà vu is caused by a mismatch between the brain’s expectations and what is actually happening. This mismatch can occur when the brain is expecting something to happen, but then something different happens.

A third theory is that déjà vu is caused by a surge of dopamine, a neurotransmitter that is associated with reward and pleasure. This surge of dopamine can cause the brain to feel like it has experienced something before, even if it has not.

Déjà vu is a relatively common experience, and it is usually harmless. However, in some cases, déjà vu can be a symptom of a more serious neurological condition, such as temporal lobe epilepsy.

If you experience déjà vu frequently or if it is accompanied by other symptoms, such as seizures, it is important to see a doctor to rule out any underlying medical conditions.

Here are some additional details about the theories of déjà vu:

• The glitch theory: This theory is based on the fact that déjà vu often occurs when people are in unfamiliar situations. The brain may be trying to make sense of the new situation by comparing it to old memories, but it may make a mistake and mistakenly believe that the current experience is a memory of a previous experience.
• The mismatch theory: This theory is based on the fact that déjà vu often occurs when people are expecting something to happen, but then something different happens. The brain may be expecting the current experience to match the old memory, but when it does not, it may trigger a feeling of déjà vu.
• The dopamine theory: This theory is based on the fact that déjà vu is often accompanied by a feeling of familiarity or familiarity. Dopamine is a neurotransmitter that is associated with reward and pleasure. The surge of dopamine may cause the brain to feel like it has experienced something before, even if it has not.

Overall, the exact reason why