Читать книгу The Power Of Youth. How To Tune Our Mind And Body For A Long And Healthy Life - Андрей Фоменко - Страница 29

Our memory is a unique storage of all the events and feelings in our lives, knowledge gained through spontaneous and focused learning, skills, and experiences. Memory is what makes us who we are, and shapes our personality. Therefore, impairment in the ability to store new memories, which is often seen in old age, reduces the quality of life.

However, the real tragedy is the process of memory degradation, the loss of an entire bunch of memories. This devastating phenomenon is specific to so-called neurodegenerative diseases, the most common of which are Alzheimer's disease and vascular dementia.

To see how to prevent these tragic age-related changes, it is important to understand what memory is, how and where it is formed, and what types of memory there are.

From a neurophysiological perspective, memory is a property of the nervous system that lies in the ability to store information about events in the world around, the body's reactions to these events, and the ability to "work" with this information: to reproduce it (recall) and change it, if necessary. A well-functioning memory is like a computer that stores all the downloaded files and opens them on demand. However, unlike a computer, our memories are not stored in folders – they are "written" in neural connections.

When we encounter new information (for example, when we begin to learn a foreign language) or new experiences (when we try to learn to drive a car), our nerve cells start to form new pathways in the brain with the help of projections and synapses. If we do not go back to that experience again, the connections disappear. Therefore, if a person starts to learn a foreign language, but soon quits, the next time they must learn again almost from scratch.

However, if information or action is referred to repeatedly, a hardly noticeable "path" in thickets of nerve endings gradually turns into a well-trod "road," and then into a high-speed "highway." And now we are, almost without thinking, speaking a new language, and driving on automatic. This indicates that "files" with the necessary information are firmly stored on our "computer."

SHORT TERM MEMORY

Some neural connections exist for a very short time: seconds and minutes, which is characteristic of short-term memory. Short-term memory allows the brain to work with small portions of information coming into it at the current time. Information can come both from external sources (what we see, hear, and feel at the moment) and from the depths of our memory – purposeful, or spontaneous recollection.

Areas in the frontal and parietal lobes of the brain, anterior cingulate cortex, and areas of basal ganglia are responsible for short-term memory.

The information storage time in short-term memory is usually no more than 20–30 seconds, in addition, it holds a very limited amount of information. According to various estimates, in a short time, a person can hold in memory from 4 to 7 objects. But there are also various techniques allowing to increase the number of memorized objects, for example, to group them by some principles or form associations. With constant repetition, "mental objects" move from short-term memory to long-term.

A form of short-term memory is working (operative) memory, allowing one to remember necessary information for just a few seconds. For example, enter the digits of a code sent by a bank to make a purchase, or type the phone number, dictated by a new friend, in the contact book. Working memory state is one of the most significant criteria used to assess a person's cognitive reserve. Its impairment is often observed with brain aging and can be considered one of the first signs of age-related dementia.

LONG TERM MEMORY

Unlike short-term memory, long-term memory is quite capable, both in terms of storage time (many memories can last until the end of life) and in terms of volume. In addition, many parts of the brain are involved in the formation of long-term memories. Long-term memory is divided into explicit and implicit.

Explicit memory allows one to consciously operate with information stored in memory, both personal experiences (episodic memory) and facts (semantic memory). The place where episodic explicit memory is stored is an area of the brain called the hippocampus. It keeps the information about, for example, going on vacation with your parents as a child and having coffee with a friend last week. Huge amounts of knowledge are stored in the cerebral cortex: here, for example, information concerning various facts, language, etc. is placed.

Amygdala is responsible for storing emotionally loaded information. Due to the neural connections in this structure, as well as the connections between the amygdala, hippocampus, and cerebral cortex, we can for many years remember situations in which we experienced a strong feeling of joy, shame, or fear. In addition, the amygdala plays a key role in the creation of new memories associated with fear. Therefore, the peculiarities of memory formation in the amygdala are actively studied by specialists involved in post-traumatic stress disorder, people who "run away" from the solution of life's tasks, because of the fear they once experienced, etc.

Implicit long-term memory is formed without consciousness: we can use it without a detailed recall process. The key brain structures responsible for storing implicit information are the basal ganglia and the cerebellum. Basal ganglia (or basal nuclei) are structures that are clusters of gray matter (nerve cell bodies) located deep in hemispheres between the frontal lobes and above the brain stem (on the border of the conscious and unconscious).

The basal nuclei store information about received rewards, and motor skills, so this structure plays a key role in the development of motor habits (piano playing, cycling, dancing, driving), that require less involvement of consciousness in the process of skills implementation as we learn. Lesion of the basal ganglia underlies the motor disorders in Parkinson's disease.