The amygdala, otherwise called the amygdala, is a small accumulation of gray matter. It is about him that we will talk. The amygdala (functions, structure, location and its defeat) has been studied by many scientists. However, we still do not know everything about him. Nevertheless, enough information has already been accumulated, which is set out in this article. Of course, we will present only the basic facts related to such a topic as the amygdala of the brain.
Briefly about the amygdala
It is rounded and is located inside each of the cerebral hemispheres (that is, there are only two of them). Its fibers are mostly connected to the organs of smell. However, a number of them are also suitable for the hypothalamus. Today it is obvious that the functions of the amygdala have a certain relationship with the mood of a person, with the feelings he experiences. In addition, it is possible that they relate to the memory of recent events.
The connection 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, probe or disease damages it, or if it is stimulated during the experiment, significant emotional changes are observed. Note that the amygdala is very well located and connected with other parts of the nervous system. Thanks to this, it acts as the center of regulation of our emotions. It is here that all signals from the primary sensory and motor cortex, from the occipital and parietal lobes of the brain, as well as from a part of the associative cortex, come. Thus, it is one of the main sensory centers of our brain. Tonsils are connected with all its sites.
The structure and location of the amygdala
It is a structure of the finite brain that has a rounded shape. The amygdala refers to the basal nuclei located in the hemispheres of the brain. It belongs to the limbic system (its subcortical part).
There are two tonsils in the brain, which are located one in each of the two hemispheres. The amygdala is located in the white matter of the brain, inside its temporal lobe. It is located anterior to the top of the lower horn of the lateral ventricle. The amygdala of the brain are located posterior to the temporal pole by about 1.5-2 centimeters. They border the hippocampus.
Three groups of cores are included in their composition. The first is basolateral, which refers to the cerebral cortex. The second group is corticomedial. It refers to the olfactory system. The third is central, which is associated with the nuclei of the brain stem (responsible for controlling the autonomic functions of our body), as well as with the hypothalamus.
The value of the amygdala
The amygdala is a part of the limbic system of the human brain, which is very important. As a result of its destruction, aggressive behavior or a lethargic, apathetic state is observed. The amygdala of the brain due to its connections with the hypothalamus affects both reproductive behavior and the endocrine system. The neurons located in them are diverse in function, form, as well as the neurochemical processes that occur in them.
Among the functions of the tonsils can be noted the provision of defensive behavior, emotional, motor, vegetative reactions, as well as the motivation of conditioned reflex behavior. Undoubtedly, these structures determine the mood of a person, his instincts, feelings.
Polysensor cores
The electrical activity of the amygdala is characterized by different-frequency and different-amplitude vibrations. Background rhythms correlate with heartbeats, breathing rhythm. Tonsils are able to respond to skin, olfactory, interoceptive, auditory, visual irritations. Moreover, these irritations are the cause of changes in the activity of each of the tonsil nuclei. In other words, these cores are multi-sensory. Their response to external stimuli, as a rule, lasts up to 85 ms. This is significantly less than the reaction to the same irritations characteristic of the new cortex.
It should be noted that the spontaneous activity of neurons is very well expressed. It can be inhibited or enhanced by sensory irritations. A significant part of neurons is polysensor and polymodal and synchronizes with the theta rhythm.
The consequences of tonsil nuclei irritation
What happens when the tonsils are irritated? Such an effect will lead to a pronounced parasympathetic effect in relation to the activity of the respiratory and cardiovascular systems. In addition, blood pressure will decrease (in rare cases, it, on the contrary, will increase). Heart rate will slow down. There are extrasystoles and arrhythmias. The cardiac tone may not change. The decrease in heart rate observed when exposed to the amygdala is characterized by a long latent period. In addition, it has a long aftereffect. Respiratory depression is also observed with irritation of the tonsils, sometimes a cough reaction occurs.
If you artificially activate the amygdala, there will be reactions of chewing, licking, sniffing, salting, swallowing; moreover, 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 due to the connection with the hypothalamus, which is the regulator of various internal organs.
The amygdala is also involved in the formation of memory, which is associated with events that have an emotional coloring. Violations in his work cause various types of pathological fear, as well as other emotional disorders.
Communication with visual analyzers
The connection of the tonsils with visual analyzers is carried out mainly through the cortex located in the cranial fossa (posterior). With this connection, the amygdala affects the processing of information in arsenal and visual structures. There are several mechanisms for this effect. We offer to consider them in more detail.
One of these mechanisms is a peculiar "coloring" of incoming visual information. It occurs due to the presence of its own high-energy structures. One or another emotional background is superimposed on the information that goes to the cortex by visual radiation. It is interesting that if the tonsils at this moment are oversaturated with negative information, even a very funny story will not be able to amuse a person, since the emotional background will not be prepared to analyze it.
In addition, the emotional background associated with tonsils has an effect on the human body as a whole. For example, the information that these structures return and which is then processed in programs makes us switch, for example, from reading a book to contemplating nature, creating this or that mood. Indeed, in the absence of mood, we will not read the book, even the most interesting one.
The defeat of the 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, sedation, as well as inability to aggression and rage. Animals with amygdala are very gullible. Monkeys, for example, without fear approach the viper, which usually causes them to flee, horror. Apparently, the total defeat of the amygdala leads to the fact that some unconditioned reflexes present from birth disappear, the action of which implements a memory of impending danger.
Statmin and its meaning
In many animals, especially mammals, fear is one of the most powerful emotions. Scientists have proved that the protein statmin is responsible for the development of acquired types of fear and for the work of congenital ones. Its largest concentration is observed just in the amygdala. For the purpose of the experiment, scientists blocked the gene that is responsible for the production of statin in experimental mice. What did this lead to? Let's figure it out.
The results of experiments on mice
They began to ignore any danger, even in cases when the mice instinctively feel it. For example, they ran through the open areas of the labyrinths, despite the fact that their relatives usually stay in places that are safer from their point of view (they prefer tight corners in which they are hidden from prying eyes).
One more example. Ordinary mice froze in horror at the repetition of a sound accompanied by a shock on the eve. Mice lacking statin perceived it as a normal sound. The lack of the “fear gene” at the physiological level led to the fact that the long-term synaptic connections between neurons were weakened (it is believed that they provide memorization). The greatest weakening was observed in those parts of the nerve networks that go to the tonsils.
In this case, experimental mice retained the ability to learn. For example, they memorized a path through a maze found once, no worse than ordinary mice.