The term “hallucination” was first introduced by the French psychiatrist Jean Escarole in 1817. For all the past scientists have been unable to determine exactly why there are visual images, and that this moment occurs in the human brain. Researchers from the University of Oregon recently gave another proof that the cause of visual hallucinations is weak activity of the brain. This was proven in an experiment with mice.
From previous studies it was known that visual hallucinations caused by schizophrenia or substance caused by activity of brain receptors of serotonin-2A. As they actively participate in the generation of visual images, the researchers decided to feed stimulating these receptors, the drug group of laboratory mice.
To understand what the mouse really sees hallucinations, scientists helped the sudden motion of the feet and heads of animals. In the course of studying brain activity, they made a very unexpected conclusion — when the mouse sees hallucinations, nerve signalling in the visual cortex remains in a weakened state. This means that the drug caused hallucinations, reducing the amount of visual information in the brain — such a result seemed to the researchers are quite contradictory.
It was believed that visual hallucinations are caused by high activity of brain neurons. We were surprised to find that the hallucinogenic drug instead leads to a decrease in activity in the visual cortex.
Chris Neill, senior author of the study
The researchers came to the conclusion that the reduction of activity in the visual cortex leads to the fact that other areas of the brain feel the lack of information and begin to fill the void of non-existent images. It is quite similar to the truth — one need only recall the experiment in which a poker player rich Alati began to see hallucinations, while being in complete darkness. In an isolated room of his brain felt the lack of information, and began to invent new images.
The new discovery will help in carrying out the following experiments. For example, in the future, the researchers want to conduct gene manipulation to study brain activity in more detail. Scientists hope that eventually they will be able to create a method of alleviating the consequences of schizophrenia and other problems associated with hallucinations.
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