The feeling of fear, like any other strong emotion, causes a significant surge in the body's activity. This is manifested by the release of various hormones that cause an increase in blood pressure, heart rate and muscle tone, increased breathing, changes in perception, and other less noticeable effects. Along with this, there is a change in the activity of individual parts of the brain. The change in the hormonal background in a person experiencing fear was described in detail by me in the article The Hormone of Fear. Now I would like to focus on in which parts and parts of the brain the changes are most significant.
Which part of the brain is responsible for fear
Emotions in general, and fear in particular, are primarily responsible for the limbic system. This is a rather ancient part of the brain, in the embryo it forms immediately after the trunk. The limbic system got this name because of its shape - it bends around the top of the trunk in a ring-like manner, forming a kind of limb. Anatomically, it connects the spinal cord with the brain, being, as it were, an intermediary between the reflex part of the human being and the higher mental functions localized in the cerebral cortex.
In the process of evolution, the rudiments of the limbic system (neostriatum) already appear in reptiles, although it is difficult to name such formations as a limbic system. Therefore, in amphibians and reptiles, emotional life is extremely scarce, if at all we can talk about it. But their education has reached perfection, which is sometimes called the "reptilian brain". These creatures are endowed with a perfect set of reactions to danger, food and a sexual partner, which makes them good specialists in survival at a primitive level.
With the development of the limbic system in evolutionarily more perfect animals, emotions become richer and thinner, giving them new tools, including new fears. A more developed emotional sphere makes it possible to take care of the offspring, which significantly increases the chances of survival. At an even higher level, emotions allow for complex intraspecific communication, which makes a gregarious lifestyle possible. But with the development of emotions, new, unknown to reptiles, shades and varieties of fear appear. For example, concern about the cubs left for a while. Or fear of dropping to a lower level in the hierarchy of the community.
If we talk about fear as such, then its center in the brain can be considered the amygdala (amygdala, amygdolar complex, amygdala). It is part of the limbic system and consists of two formations located inside the median temporal lobes. If we imagine the brain as transparent, we will see them as if hanging down the sides of the belt formed by the limbic system. Reasoning quite simply and schematically, we can say that fear is deep in the temples.
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Action of the center of fear in the brain
Because fear is a key element in survival, the amygdala is anatomically connected to all major regions of the brain. The amygdala continuously receives signals from the olfactory, tactile, visual and auditory analyzers, meticulously examining them for possible threats. And if one is noticed, the fright mechanism is triggered. For this, connections with the hypothalamus are used, which begins to produce corticoliberin, a hormone that causes anxiety and makes you distract from business and focus on danger. The signal transmitted from the amygdala to the blue spot in the brain stem leads to the secretion of the well-known norepinephrine. Signals also go to the striatum, central gray matter and other centers of the nervous system responsible for the motor sphere. Hence the effect on muscle tone, heart rate and even on the intestines,which, as you know, can give a very curious reaction to danger.
But it’s not that simple. One of the functions of the amygdala is the formation of emotional memory, especially for the complexes of signals that precede the occurrence of danger. But the danger can be not only immediate, in the form of an approaching predator. A student who cannot solve a problem on the exam seems to be in no danger - a cozy, quiet, bright and warm audience, everything is peaceful and friendly. But, nevertheless, he may feel fear at this moment. And faceless information about a change in the share price of some in general can lead to a heart attack. This means that not only signals from receptors are involved in the formation of emotional memory, but also connections with the youngest parts of the brain, which are responsible for the most complex mental processes.
Experiments on influencing the centers of fear in the brain
Let's start with a description of natural experiments that nature itself sometimes puts on people. There is Urbach-Wite disease, which completely removes fear from a person. This is a rather rare pathology, since its discovery in 1929 there are less than three hundred recorded cases in the world. This disease destroys the amygdala, and often causes coarsening of the mucous membranes and skin, or thickens the tissues in the area of the amygdala itself, which can provoke epileptic seizures. Otherwise, Urbach-Wite disease is not dangerous and does not directly lead to premature death, although it can accelerate its onset due to loss of vigilance.
The most famous patient today is a woman living in the United States, in the state of Iowa. Her amygdala was completely destroyed in adolescence, which made it possible for her emotional sphere to form normally, with the exception of a feeling of fear, which she does not experience at all. On the one hand, this is, of course, pleasant, and to some, the absence of fear may even seem to be a very desirable effect, but in reality it is not. No disease can be better than health. This woman has repeatedly found herself in situations where her fear was silent, and she remained alive only by pure chance.
Experiments on the formation of phobias are also noteworthy. A group of volunteers was shown a picture followed by an electric shock. After a certain number of impressions, the experience solidified, and the subjects began to feel fear at the sight of the picture. The role of the limbic system and the amygdala in the formation of phobia was established by hardware methods. But this is not the main thing. The resulting phobia in everyone was cured by purely psychological methods. And this clearly shows the possibility and even the need to treat phobias without the destructive use of drugs. That is, a phobia is not so much a disease as a result of learning. And it should be treated not by direct influence on the brain, but by retraining, that is, by cognitive-behavioral methods.
Military developments to suppress fear are also interesting. This is mainly pharmacology, and the developments are classified, but it is reliably known that drugs to suppress fear exist. Many readers of these lines who suffer from fear will certainly make attempts to find out something about such drugs. I warn you right away: this is a road to nowhere. Tooth decay is not treated with pain-relieving injections, nor is fear treated with military pills. They are given to the soldier to risk, die and maim his brain for the sake of completing a combat mission. Do you need it?
Feelings of fear, along with anger and sexual feelings, are one of the first emotions experienced by a living being. This, without exaggeration, a wonderful feeling allows you to avoid danger before it manifests itself in full and turned into pain, leaving no chance of salvation. It was the feeling of fear that was one of the first results of the analytical work of the primitive brain, endowing the body with a new powerful survival tool. Therefore, it is not surprising that the part of the brain responsible for fear is located in one of the oldest parts of the brain. Take care of your fear as it protects you. Rejoice and be proud that you have a magical fear mechanism that allows you to survive much more efficiently than those who have it weakened or broken. And if you have problems with fear, then you should not rely on pills. Instead, we need to resort to reliable and harmless psychological correction methods.
Author: Valentin Rykov
