Where is the amygdala and what does it perform?

The almond-shaped body, otherwise called the amygdala, is a small cluster of gray matter. It's about him that we'll talk. The almond-shaped body (functions, structure, location and its defeat) has been studied by many scientists. However, we still do not know everything about it. Nevertheless, enough information has already been accumulated, which is outlined in this article. Of course, we will only present the basic facts associated with such an issue as the amygdala of the brain.

Briefly about the amygdala

It is rounded and located inside each of the brain's hemispheres (that is, there are only two of them). Its fibers are mostly connected with the organs of smell. However, a number of them are also suitable for the hypothalamus. To date, it is clear that the functions of the amygdala have a certain relation to the mood of a person, to the feelings that he experiences. In addition, it is possible that they relate to the memory of events that have occurred recently.

Relationship of the amygdala with other parts of the central nervous system

It should be noted that the amygdala has very good "connections". If a scalpel, a probe or disease is damaged, or if it is stimulated during the experiment, there are significant emotional shifts. Note that the amygdala is very well located and is associated with other parts of the nervous system. Due to this, it acts as the center of regulation of our emotions. It is here that all signals come from the primary sensory and motor cortex, from the occipital and parietal lobes of the brain, and also from part of the associative cortex. Thus, it is one of the main sensory centers of our brain. Tonsils are connected with all its parts.

The structure and location of the amygdala

It is a structure of the final brain, which has a rounded shape. The almond-shaped body belongs to the basal cores, located in the cerebral hemispheres. It belongs to the limbic system (its subcortical part).

In the brain there are two tonsils, which are located one in each of the two hemispheres. The almond-shaped body is in the white matter of the brain, inside its temporal lobe. It is located anterior to the apex of the lower horn of the lateral ventricle. The almond-shaped bodies of the brain are posterior to the temporal pole by about 1.5-2 centimeters. They border on the hippocampus.

Three groups of nuclei are included in their composition. The first is a basolateral one, which refers to the cerebral cortex. The second group is corticomedial. It refers to the olfactory system. The third is central, which is connected with the nuclei of the brain stem (responsible for controlling the autonomic functions of our body), as well as with the hypothalamus.

Significance of the amygdala

The amygdala is part of the limbic system of the human brain, which is very important. As a result of its destruction, there is an aggressive behavior or a sluggish, apathetic state. Almond-like brain bodies due to their connections to the hypothalamus affect both reproductive behavior and the endocrine system. The neurons in them are diverse in function, form, and also in the neurochemical processes taking place in them.

Among the functions of the tonsils can be noted the provision of defensive behavior, emotional, motor, autonomic responses, as well as motivation for conditioned reflex behavior. Undoubtedly, these structures determine the mood of a person, his instincts, feelings.

Polysensorynost kernels

The electrical activity of the amygdala is characterized by various frequency and different amplitude fluctuations. Background rhythms correlate with cardiac contractions, the rhythm of breathing. Tonsils are able to react to skin, olfactory, interoceptive, auditory, visual irritations. In this case, these stimuli cause the activity of each of the amygdala nuclei to change. In other words, these kernels are polysensory. Their reaction to external stimuli, as a rule, lasts up to 85 ms. This is substantially less than the reaction to the same irritations characteristic of the new crust.

It should be noted that the spontaneous activity of neurons is very well expressed. It can be braked or strengthened by sensory stimuli. A significant part of the neurons are polysensory and poly-modal and synchronized with the theta rhythm.

Effects of irritation of the amygdala nuclei

What happens when the tonsils are irritated? Such an effect will lead to a pronounced parasympathetic effect on the activity of the respiratory and cardiovascular systems. In addition, blood pressure will drop (in rare cases it will, on the contrary, increase). The heart rhythm slows down. There will be extrasystoles and arrhythmias. Heart tone may not change. The decrease in the rhythm of heartbeats, observed when exposed to the amygdala, is characterized by a prolonged latent period. In addition, it is characterized by a long aftereffect. Respiratory depression is also observed with irritation of the amygdala nuclei, sometimes a cough reaction occurs.

If the almond-shaped body is artificially activated, chewing, licking, sniffing, salivating, swallowing reactions will appear; And these effects occur with a significant latent period (after irritation it takes up to 30-45 seconds). The various effects that are observed in this case arise from the connection with the hypothalamus, which is the regulator of the work of various internal organs.

The almond-shaped body also participates in the formation of memory, which is associated with events that have an emotional coloring. Violations in his work cause different types of pathological fear, as well as other emotional disorders.

Communication with visual analyzers

The connection of the tonsils with the visual analyzers is carried out mainly through the cortex located in the cranial fossa (posterior) region. With this connection, the amygdala bodies influence the processing of information in arsenal and visual structures. There are several mechanisms of this impact. We propose to consider them in more detail.

One of these mechanisms is a kind of "coloring" of incoming visual information. It occurs due to the presence of its own high-energy structures. On the information that goes to the cortex on visual radiation, this or that emotional background is superimposed. It is interesting that if tonsils are oversaturated with negative information at that moment, even a very funny story can not cheer people up, as the emotional background will not be prepared for analyzing it.

In addition, the emotional background associated with tonsils affects the human body as a whole. For example, the information returned by these structures and then processed in programs, makes us switch, say, from reading a book to contemplation of nature, creating this or that mood. After all, if there is no mood, we will not read a book, even the most interesting one.

The defeat of amygdala in animals

Their damage in animals leads to the fact that the autonomic nervous system becomes less capable of realizing and organizing behavioral reactions. This can lead to the disappearance of fear, hypersexuality, calming, and also inability to aggression and rage. Animals with an affected almond-shaped body become very gullible. Monkeys, for example, without fear approach a viper, which usually causes them to escape, horror. Apparently, the total defeat of amygdala bodies leads to the fact that some unconditioned reflexes present from birth are lost, the action of which realizes the memory of the imminent danger.

Statin and its meaning

In many animals, especially in mammals, fear is one of the strongest emotions. Scientists have proved that the protein statin is responsible for the development of acquired types of fear and for the work of congenital. Its greatest concentration is observed just in the amygdala. For the purposes of the experiment, scientists blocked the gene, which is responsible for the production of statin, in experimental mice. What did this lead to? Let's figure it out.

Results of experiments on mice

They began to ignore any danger, even in cases where the mouse instinctively feels it. For example, they ran through open areas of labyrinths, despite the fact that their relatives usually stay in places safer from their point of view (preferring close entrances in which they are hidden from other people's eyes).

One more example. The usual mice were frozen in horror at the repetition of the sound, which was accompanied on the eve by a current blow. Mice deprived of a statin perceived it as a normal sound. The lack of a "fear gene" at the physiological level led to the fact that the long-term synaptic connections existing between neurons appeared to be weakened (it is believed that they provide memorization). The greatest attenuation was observed in those parts of the nerve networks that go to the tonsils.

Experimental mice at the same time retained the ability to learn. For example, they memorized a path through a labyrinth found once, no worse than ordinary mice.