As soon as the annoying mosquito sits on us, we immediately look for it with our eyes to ruthlessly swat it. Have you ever wondered that this instant response is the result of a mental process? And it's much more complicated than it sounds. After all, the brain needs to match tactile sensations with information about the surrounding space.
Cognitive Neurology Research Group (GRNC) Professors Salvador Soto-Faraco and Elena Azanyon are spearheading a new study of the processes involved in human response.
“The main task of the study is to show that at an unconscious level a person quickly learns where his tactile sensations come from, but realizes this only after the brain forms a picture of the origin of tactile information in spatial coordinates,” explains Salvador Soto-Faraco. The coexistence in the brain of many anatomical pictures about the position and location of body parts in space can in some cases cause confusion. For example, when a person is in an unusual position for him. “To solve 10 such tasks per second, the brain needs to make a single whole of all the information received. The study helped us understand how this process works and how the brain rebuilds its picture of space when it encounters a problem,”comments the professor.
Here's a simple example to show that it can be difficult to analyze information: cross your arms in front of you, connect your fingers and palms so that the left hand is on the right side and the right hand is on the left. If you are told to move a finger of a certain hand, it is most likely that you will move the same finger but on the other hand.
To determine the time it takes for the brain to carry out these operations, the GRNC researchers have developed a special methodology. First, a short flash of the LED is emitted to the subject's hand in a calm state. Then - on the hand, which previously received tactile irritation. In both cases, the scientists measured the rate of reaction to the outbreak and compared the results. In the main experiment, participants were asked to cross their arms so that the left hand was on the right and the right was on the left. The procedure confirmed that the brain is facing a problem as the external position of the hands contradicts the anatomical one.
Each participant went through about 600 such experiments. The time between the sensation of tactile stimulation and obtaining a visual image of the stimulus source and its location was different in different cases. It was noted that the responses of the subjects changed markedly as the time between skin irritations decreased. For 60 milliseconds or less, the brain tried to identify the part of the body where the tactile stimulus was felt. The impact on the left hand, which is in the field of view of the right, is still perceived by the brain as an effect on the left side of the body. It takes the brain 200 milliseconds to determine if the stimulus was on the right side.
Despite the fact that the brain first analyzes the anatomical part of the body, and then its location, the subjects always accurately showed the place of irritation.
“The research results allow us to understand exactly how the information about tactile sensations is processed. The first stage of identifying a body part occurs on an unconscious level. Thus, the brain warns us against unwanted mistakes,”says Soto-Farako. "This process is similar to how we would usually rush to draft rough notes and then edit them and get the final version."
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