What does the human brain consist of? Transmission of signals from auditory analyzers to the brain Area of ​​orientation, memory and imagination

Principles of information transmission and structural organization of the brain

Plan

Introduction

Principles of information transmission and structural organization of the brain

Interconnections in simple nervous systems

Complex neural networks and higher brain functions

Structure of the retina

Neuron patterns and connections

Cell body, dendrites, axons

Methods for identifying neurons and tracing their connections. Non-nervous elements of the brain

Grouping cells according to function

Cell subtypes and function

Convergence and divergence of connections

Literature

Introduction

The terms “neurobiology” and “neurosciences” came into use in the 60s of the 20th century, when Stephen Kuffler created the first department at Harvard Medical School, whose staff included physiologists, anatomists and biochemists. Working together, they solved problems of the functioning and development of the nervous system and explored the molecular mechanisms of the brain.

The central nervous system is a continuously working conglomerate of cells that constantly receive information, analyze it, process it and make decisions. The brain is also able to take the initiative and produce coordinated, efficient muscle contractions for walking, swallowing, or singing. To regulate many aspects of behavior and to directly or indirectly control the entire body, the nervous system has a huge number of lines of communication provided by nerve cells (neurons). Neurons are the basic unit, or building block, of the brain

Interconnections in simple nervous systems

Events that occur during the implementation of simple reflexes can be traced and analyzed in detail. For example, when the knee ligament is struck with a small hammer, the muscles and tendons of the thigh are stretched and electrical impulses travel along sensory nerve fibers to the spinal cord, where motor cells are excited, producing impulses and activating muscle contractions. The end result is straightening of the leg at the knee joint. Such simplified circuits are very important for regulating muscle contractions that control limb movements. In such a simple reflex, in which a stimulus leads to a specific output, the role of signals and interactions of just two types of cells can be successfully analyzed.

Complex neural networks and higher brain functions

Analyzing the interaction of neurons in complex pathways involving literally millions of neurons is significantly more difficult than analyzing simple reflexes. Re-

Providing information to the brain for the perception of sound, touch, smell or sight requires the sequential engagement of neuron by neuron, just as when performing a simple voluntary movement. A major challenge in analyzing neuronal interactions and network structure arises from the dense packing of nerve cells, the complexity of their interconnections, and the abundance of cell types. The brain is structured differently than the liver, which is made up of similar populations of cells. If you have discovered how one area of ​​the liver works, then you know a lot about the liver as a whole. Knowing about the cerebellum, however, does not tell you anything about the functioning of the retina or any other part of the central nervous system.

Despite the enormous complexity of the nervous system, it is now possible to analyze the many ways in which neurons interact during perception. For example, by recording the activity of neurons along the path from the eye to the brain, it is possible to trace signals first in cells that specifically respond to light, and then, step by step, through successive switches, to higher centers of the brain.

An interesting feature of the visual system is its ability to distinguish contrasting images, colors and movements over a huge range of color intensities. As you read this page, signals within the eye make it possible for black letters to stand out on a white page in a dimly lit room or in bright sunlight. Specific connections in the brain form a single picture, even though the two eyes are located separately and scan different areas of the outside world. Moreover, there are mechanisms that ensure the constancy of the image (even though our eyes are constantly moving) and provide accurate information about the distance to the page.

How do nerve cell connections provide such phenomena? Although we are not yet able to provide a complete explanation, much is now known about how these properties of vision are mediated by simple neural networks in the eye and early switching stages in the brain. Of course, many questions remain about what the connections are between neuronal properties and behavior. So, in order to read a page, you must maintain a certain position of your body, head and hands. Further, the brain must ensure constant hydration of the eyeball, constant breathing and many other involuntary and uncontrolled functions.

The functioning of the retina is a good example of the basic principles of the nervous system.

Rice. 1.1. Pathways from the eye to the brain via the optic nerve and optic tract.

Structure of the retina

Analysis of the visual world depends on information coming from the retina, where the first stage of processing occurs, setting the limits for our perception. In Fig. Figure 1.1 shows the paths from the eye to the higher centers of the brain. The image that enters the retina is inverted, but in all other respects it represents a bona fide representation of the external world. How can this picture be transmitted to our brain through electrical signals that originate in the retina and then travel along the optic nerves?

Neuron patterns and connections

In Fig. Figure 1.2 shows the different types of cells and their location in the retina. Light entering the eye passes through layers of transparent cells and reaches the photoreceptors. Signals transmitted from the eye along the fibers of the optic nerve are the only information signals on which our vision is based.

The scheme for the passage of information through the retina (Fig. 1.2A) was proposed by Santiago Ramon y Cahal1) at the end of the 19th century. He was one of the greatest researchers of the nervous system and conducted experiments on a wide variety of animals. He made a significant generalization that the shape and arrangement of neurons, as well as the region of origin and final target of neuronal signals in a network, provide critical information about the functioning of the nervous system.

In Fig. Figure 1.2 clearly shows that the cells in the retina, as in other parts of the central nervous system (CNS), are very densely packed. At first, morphologists had to tear apart nervous tissue to see individual nerve cells. Techniques that stain entire neurons are virtually useless for examining cell shape and connectivity because structures such as the retina appear as a dark patch of intertwined cells and processes. Electron micrograph in Fig. Figure 1.3 shows that the extracellular space around neurons and supporting cells is only 25 nanometers wide. Most of the drawings of Ramón y Cajal were made using the Golgi staining method, which stains, by an unknown mechanism, only a few random neurons from the entire population, but these few neurons are completely stained.

Rice. 1.2. Structure and connections of cells in the mammalian retina. (A) Scheme of the signal direction from the receptor to the optic nerve according to Ramon y Cajal. (B) Ramon y Cajal distribution of retinal cellular elements. (C) Drawings of rods and cones of the human retina.

Rice. 1.3. Dense packing of neurons in the monkey retina. One rod (R) and one cone (C) are labeled.

Scheme in Fig. Figure 1.2 shows the principle of the orderly arrangement of neurons in the retina. It is easy to distinguish between photoreceptors, bipolar cells and ganglion cells. The direction of transmission is from input to output, from photoreceptors to ganglion cells. In addition, two other types of cells, horizontal and amacrine, form connections that connect different pathways. One of the goals of the neurobiology present in Ramon y Cajal's drawings is the desire to understand how each cell participates in creating the picture of the world that we observe.

Cell body, dendrites, axons

The ganglion cell shown in Fig. 1.4 illustrates the structural features of nerve cells inherent in all neurons of the central and peripheral nervous system. The cell body contains the nucleus and other intracellular organelles common to all cells. The long extension that leaves the cell body and forms a connection with the target cell is called an axon. The terms dendrite, cell body, and axon are applied to processes at which incoming fibers form contacts that act as receiving stations for excitation or inhibition. In addition to the ganglion cell, in Fig. Figure 1.4 shows other types of neurons. The terms used to describe the structure of a neuron, particularly dendrites, are somewhat controversial, but nevertheless they are convenient and widely used.

Not all neurons conform to the simple cell structure shown in Fig. 1.4. Some neurons do not have axons; others have axons on which connections are formed. There are cells whose dendrites can conduct impulses and form connections with target cells. While a ganglion cell conforms to the blueprint of a standard neuron with dendrites, cell body, and axon, other cells do not conform to this standard. For example, photoreceptors (Fig. 1.2C) have no obvious dendrites. The activity of photoreceptors is not caused by other neurons, but is activated by external stimuli, lighting. Another exception in the retina is the absence of photoreceptor axons.

Methods for identifying neurons and tracing their connections

Although the Golgi technique is still widely used, many new approaches have facilitated the functional identification of neurons and synaptic connections. Molecules that stain the entire neuron can be injected through a micropipette, which simultaneously records the electrical signal. Fluorescent markers such as Lucifer yellow reveal the finest processes in a living cell. Intracellular markers such as the enzyme horseradish peroxidase (HRP) or biocytin can be introduced; once fixed, they form a dense product or glow brightly under fluorescent light. Neurons can be stained with horseradish peroxidase and with extracellular application; the enzyme is captured and transported into the cell body. Fluorescent carbocyanic dyes, upon contact with the neuron membrane, dissolve and diffuse over the entire surface of the cell.

Rice. 1.4. Shapes and sizes of neurons.

Rice. 1.5. A group of bipolar cells stained with an antibody for the enzyme phosphokinase C. Only cells containing the enzyme stained.

These techniques are very important for tracing the passage of axons from one part of the nervous system to another.

Antibodies are used to characterize specific neurons, dendrites, and synapses by selectively labeling intracellular or membrane components. Antibodies are successfully used to trace the migration and differentiation of nerve cells during ontogenesis. An additional approach to characterize neurons is hybridization in situ: specifically labeled probes label neuronal mRNA that encodes the synthesis of a channel, receptor, transmitter, or structural element.

Non-nervous elements of the brain

Glial cells. Unlike neurons, they do not have axons or dendrites and are not directly connected to nerve cells. There are a lot of glial cells in the nervous system. They perform many different functions related to signal transmission. For example, the axons of the retinal ganglion cells that make up the optic nerve conduct impulses very quickly because they are surrounded by an insulating lipid sheath called myelin. Myelin is formed by glial cells that wrap around axons during ontogenetic development. Glial cells in the retina are known as Müller cells.

Grouping cells according to function

A remarkable property of the retina is the arrangement of cells according to function. The cell bodies of photoreceptors, horizontal cells, bipolar cells, amacrine cells, and ganglion cells are arranged in distinct layers. Similar layering is observed throughout the brain. For example, the structure where the fibers of the optic nerve terminate (the lateral geniculate body) consists of 6 layers of cells that are easy to distinguish even with the naked eye. In many areas of the nervous system, cells with similar functions are grouped into distinct spherical structures known as nuclei (not to be confused with the cell nucleus) or ganglia (not to be confused with retinal ganglion cells).

Cell subtypes and function

There are several distinct types of ganglion, horizontal, bipolar, and amacrine cells, each with characteristic morphology, transmitter specificity, and physiological properties. For example, photoreceptors are divided into two easily distinguishable classes - rods and cones - which perform different functions. Elongated rods are extremely sensitive to the slightest changes in lighting. As you read this page, the ambient light is too bright for the wands, which only function in low light after a long period in the dark. Cones respond to visual stimuli in bright light. Moreover, cones are further classified into photoreceptor subtypes that are sensitive to red, green, or blue light. Amacrine cells are a striking example of cellular diversity: more than 20 types can be distinguished according to structural and physiological criteria.

The retina thus illustrates the deepest problems of modern neurobiology. It is not known why so many types of amacrine cells are needed and what different functions each of these cell types has. It is sobering to realize that the function of the vast majority of nerve cells in the central, peripheral and visceral nervous systems is unknown. At the same time, this ignorance suggests that many of the basic principles of the robotic brain are not yet understood.

Convergence and divergence of connections

For example, there is a strong decrease in the number of cells involved along the path from receptors to ganglion cells. The outputs of more than 100 million receptors converge on 1 million ganglion cells, the axons of which make up the optic nerve. Thus, many (but not all) ganglion cells receive input from a large number of photoreceptors (convergence) through intercalary cells. In turn, one ganglion cell intensively branches and ends on many target cells.

In addition, unlike the simplified diagram, the arrows should point outward to indicate interactions between cells in the same layer (lateral connections) and even in opposite directions - for example, back from horizontal cells to photoreceptors (reciprocal connections). Such convergent, divergent, lateral, and recurrent influences are constant properties of most neural pathways throughout the nervous system. Thus, simple step-by-step signal processing is complicated by parallel and reverse interactions.

Cellular and molecular biology of neurons

Like other types of cells in the body, neurons fully possess the cellular mechanisms of metabolic activity and the synthesis of membrane proteins (for example, ion channel proteins and receptors). Moreover, proteins of ion channels and receptors are directedly transported to localization sites in the cell membrane. Sodium- or potassium-specific channels are located on the membrane of ganglion cell axons in discrete groups (clusters). These channels are involved in the initiation and conduct of PD.

Presynaptic terminals, formed by processes of photoreceptors, bipolar cells and other neurons, contain specific channels in their membrane through which calcium ions can pass. The entry of calcium triggers the release of the transmitter. Each type of neuron synthesizes, stores and releases a specific type of transmitter(s). Unlike many other membrane proteins, receptors for specific neurotransmitters are located in precisely defined locations - postsynaptic membranes. Among membrane proteins, pump proteins or transport proteins are also known, the role of which is to maintain the constancy of the internal contents of the cell.

The main difference between nerve cells and other types of cells in the body is the presence of a long axon. Since axons do not have the biochemical "kitchen" for protein synthesis, all essential molecules must be transported to the terminals by a process called axonal transport, often over very long distances. All molecules needed to maintain structure and function, as well as membrane channel molecules, travel away from the cell body via this pathway. In the same way, molecules captured by the terminal membrane make their way back to the cell body using axonal transport.

Neurons also differ from most cells in that, with a few exceptions, they cannot divide. This means that in adult animals, dead neurons cannot be replaced.

Regulation of nervous system development

The high degree of organization of a structure such as the retina poses new problems. If a human brain is needed to build a computer, then no one controls the brain as it develops and makes connections. It is still a mystery how the correct “assembly” of parts of the brain leads to the appearance of its unique properties.

In the mature retina, each cell type is located in a corresponding layer or sublayer and forms strictly defined connections with the corresponding target cells. Such a device is a necessary condition for proper functioning. For example, for normal ganglion cells to develop, the precursor cell must divide, migrate to a specific location, differentiate into a specific shape, and form specific synaptic connections.

The axons of this cell must find, through a considerable distance (optic nerve), a certain layer of target cells in the next link of synaptic switching. Similar processes occur in all parts of the nervous system, resulting in the formation of complex structures with specific functions.

The study of the mechanisms of formation of such complex structures as the retina is one of the key problems of modern neurobiology. Understanding how the complex interconnections of neurons are formed during individual development (ontogenesis) can help describe the properties and origins of functional brain disorders. Some molecules may play key roles in neuronal differentiation, growth, migration, synapse formation, and survival. Such molecules are now being described more and more often. It is interesting to note that electrical signals regulate molecular signals that trigger axon growth and connection formation. Activity plays a role in establishing the pattern of connections.

Genetic approaches allow the identification of genes that control the differentiation of entire organs, such as the eye as a whole. Hering and colleagues studied gene expression eyeless in a fruit fly Drosophila, which controls eye development. Removing this gene from the genome results in eyes not developing. Homologous genes in mice and humans (known as small eye And aniridia) similar in structure. If a homologous gene eyeless mammals is artificially integrated and expressed in the fly, then this animal develops additional (fly-like in structure) eyes on the antennae, wings and legs. This suggests that this gene controls eye formation in the same way in a fly or mouse, despite the completely different structure and properties of insect and mammalian eyes.

Regeneration of the nervous system after injury

The nervous system not only makes connections during development, but can repair some connections after damage (your computer cannot do this). For example, axons in the hand can sprout after injury and establish connections; the hand can again move and feel touch. Similarly, in a frog, fish or invertebrate animal, following destruction in the nervous system, axonal regeneration and restoration of function are observed. After cutting the optic nerve in a frog or fish, the fibers grow back and the animal can see. However, this ability is not inherent in the central nervous system of adult vertebrates - regeneration does not occur in them. The molecular signals that block regeneration and their biological significance for nervous system function are unknown

conclusions

∙ Neurons are connected to each other in a strictly defined way.

∙ Information is transmitted from cell to cell through synapses.

∙ In relatively simple systems, such as the retina, it is possible to trace all the connections and understand the meaning of intercellular signals.

∙ Nerve cells of the brain are the material elements of perception.

∙ Signals in neurons are highly stereotyped and are the same for all animals.

∙ Action potentials can travel long distances without loss.

∙ Local gradual potentials depend on the passive electrical properties of neurons and propagate only over short distances.

∙ The special structure of nerve cells requires a specialized mechanism for the axonal transport of proteins and organelles to and from the cell body.

∙ During individual development, neurons migrate to their final locations and establish connections with targets.

∙ Molecular signals control axon growth.

Bibliography

Penrose R. THE NEW MIND OF THE KING. About computers, thinking and the laws of physics.

Gregory R. L. Intelligent Eye.

Lekah V. A. The key to understanding physiology.

Gamow G., Ichas M. Mr. Tompkins inside himself: Adventures in new biology.

Kozhedub R. G. Membrane and synoptic modifications in manifestations of the basic principles of brain function.

MAIN CHARACTERISTICS OF THE HUMAN HEARING ANALYZER

Structure and functioning of the human auditory analyzer

All sound information that a person receives from the outside world (it is approximately 25% of the total) is recognized by him using the auditory system.

The auditory system is a kind of receiver of information and consists of the peripheral part and higher parts of the auditory system.

The peripheral part of the auditory system performs the following functions:

- an acoustic antenna that receives, localizes, focuses and amplifies the sound signal;

- microphone;

- frequency and time analyzer;

An analog-to-digital converter that converts an analog signal into binary nerve impulses.

The peripheral auditory system is divided into three parts: the outer, middle, and inner ear.

The outer ear consists of the pinna and the ear canal, which ends in a thin membrane called the eardrum. The outer ears and head are components of an external acoustic antenna that connects (matches) the eardrum to the external sound field. The main functions of the external ears are binaural (spatial) perception, sound source localization, and amplification of sound energy, especially in the mid and high frequencies.

Auricle 1 in the area of ​​the outer ear (Fig. 1.a) directs acoustic vibrations into the ear canal 2, ending with the eardrum 5. The auditory canal serves as an acoustic resonator at frequencies of about 2.6 kHz, which increases the sound pressure three times. Therefore, in this frequency range the sound signal is significantly amplified, and it is here that the region of maximum hearing sensitivity is located The sound signal further affects the eardrum3.

The eardrum is a thin film 74 microns thick, shaped like a cone with its tip facing the middle ear. It forms the border with the middle ear region and is connected here to the musculoskeletal lever mechanism in the form of a hammer 4 and incus 5. The pedicle of the incus rests on the membrane of the oval window 6 inner ear 7. The hammer-incus lever system is a transformer of vibrations of the eardrum, increasing the sound pressure on the membrane of the oval window for the greatest return of energy from the air environment of the middle ear, which communicates with the external environment through the nasopharynx 8, into the area of ​​the inner ear 7, filled with incompressible fluid - perilymph.

The middle ear is an air-filled cavity connected to the nasopharynx by the Eustachian tube to equalize atmospheric pressure. The middle ear performs the following functions: matching the impedance of the air environment with the liquid environment of the cochlea of ​​the inner ear; protection from loud sounds (acoustic reflex); amplification (lever mechanism), due to which the sound pressure transmitted to the inner ear is amplified by almost 38 dB compared to that which hits the eardrum.

Fig.1. Structure of the hearing organ

The structure of the inner ear (shown expanded in Fig. 1.6) is very complex and is discussed here schematically. Its cavity 7 is a tube tapering towards the apex, coiled into 2.5 turns in the form of a snail 3.5 cm long, to which are adjacent the channels of the vestibular apparatus in the form of three rings 9. This entire labyrinth is limited by a bony septum 10. Note that in the inlet part of the tube, in addition to the oval membrane, there is a round window membrane 11, performing the auxiliary function of coordinating the middle and inner ear.

The main membrane is located along the entire length of the cochlea 12 - acoustic signal analyzer. It is a narrow ribbon of flexible ligaments (Fig. 1.6), expanding towards the top of the cochlea. The cross section (Fig. 1.c) shows the main membrane 12, bone (Reissner's) membrane 13, separating the liquid environment of the vestibular apparatus from the auditory system; along the main membrane there are layers of endings of nerve fibers of the 14th organ of Corti, connecting into a tourniquet 15.

The main membrane consists of several thousand transverse fibers length 32 mm. The organ of Corti contains specialized auditory receptors- hair cells. In the transverse direction, the organ of Corti consists of one row of inner hair cells and three rows of outer hair cells.

The auditory nerve is a twisted trunk, the core of which consists of fibers extending from the apex of the cochlea, and the outer layers from its lower sections. Having entered the brain stem, neurons interact with cells at various levels, rising to the cortex and crossing along the way so that auditory information from the left ear comes mainly to the right hemisphere, where emotional information is mainly processed, and from the right ear to the left hemisphere, where semantic information is mainly processed. In the cortex, the main hearing zones are located in the temporal region, and there is constant interaction between both hemispheres.

The general mechanism of sound transmission can be simplified as follows: sound waves pass through the sound channel and excite vibrations of the eardrum. These vibrations are transmitted through the ossicular system of the middle ear to the oval window, which pushes fluid into the upper part of the cochlea.

When the membrane of the oval window oscillates in the fluid of the inner ear, elastic vibrations occur, moving along the main membrane from the base of the cochlea to its apex. The structure of the main membrane is similar to a system of resonators with resonant frequencies localized along their length. The membrane areas located at the base of the cochlea resonate to the high-frequency components of sound vibrations, causing them to vibrate, the middle ones react to the mid-frequency ones, and the areas located near the top - to low frequencies. High-frequency components in the lymph quickly attenuate and do not affect areas of the membrane remote from the beginning.

Resonance phenomena localized on the surface of the membrane in the form of a relief, as shown schematically in Fig. 1. G, excite nerve “hair” cells located on the main membrane in several layers, forming the organ of Corti. Each of these cells has up to one hundred “hair” endings. On the outer side of the membrane there are three to five layers of such cells, and under them there is an inner row, so that the total number of “hair” cells interacting with each other layer by layer when the membrane is deformed is about 25 thousand.

In the organ of Corti, mechanical vibrations of the membrane are converted into discrete electrical impulses of nerve fibers. When the main membrane vibrates, the cilia on the hair cells bend, and this generates an electrical potential, which causes a flow of electrical nerve impulses that carry all the necessary information about the received sound signal to the brain for further processing and response. The result of this complex process is the conversion of the input acoustic signal into electrical form, which is then transmitted to the auditory areas of the brain through the auditory nerves.

The higher parts of the auditory system (including the auditory zones of the cortex) can be considered as a logical processor that identifies (decodes) useful sound signals against a background of noise, groups them according to certain characteristics, compares them with images in memory, determines their information value and makes a decision on responses. actions.

Transmission of signals from auditory analyzers to the brain

The process of transmitting nerve stimuli from hair cells to the brain is electrochemical in nature.

The mechanism of transmission of nerve stimuli to the brain is represented by the diagram in Fig. 2, where L and R are the left and right ears, 1 are auditory nerves, 2 and 3 are intermediate centers for the distribution and processing of information located in the brain stem, and 2 are the so-called . cochlear nuclei, 3 - superior olives.

Fig.2. Mechanism of transmission of nerve stimuli to the brain

The mechanism by which the sensation of pitch is formed is still subject to debate. It is only known that at lower frequencies several pulses occur for each half-cycle of sound vibration. At higher frequencies, pulses do not occur in every half-cycle, but less frequently, for example, one pulse every second period, and at higher frequencies even every third. The frequency of nerve impulses arising depends only on the intensity of stimulation, i.e. on the sound pressure level.

Most of the information coming from the left ear is transmitted to the right hemisphere of the brain and, conversely, most of the information coming from the right ear is transmitted to the left hemisphere. In the auditory parts of the brain stem, pitch, sound intensity and some characteristics of timbre are determined, i.e. Primary signal processing is performed. Complex processing processes take place in the cerebral cortex. Many of them are congenital, many are formed in the process of communication with nature and people, starting from infancy.

It has been established that in most people (95% of right-handers and 70% of left-handers) the left hemisphere is allocated and processed; semantic signs of information, and on the right - aesthetic ones. This conclusion was obtained in experiments on the biotic (bifurcated, separate) perception of speech and music. When listening with the left ear to one set of numbers and the right ear to another, the listener gives preference to the one that is perceived by the right ear and information about which is received by the left hemisphere. On the contrary, when listening to different melodies with different ears, preference is given to the one that is listened to by the left ear and the information from which enters the right hemisphere.

Nerve endings under the influence of excitation generate impulses (i.e., practically a signal already encoded, almost digital), transmitted along nerve fibers to the brain: at the first moment up to 1000 impulses/s, and after a second - no more than 200 due to fatigue, which determines adaptation process, i.e. decrease in perceived loudness with prolonged exposure to a signal.

Here we will also talk about information. But in order not to get confused in different interpretations of the same word, let's immediately clearly define what information we will be talking about. So, the brain is capable of recording only connections. The brain remembers this type of information (connection). The process by which it does this is called the “Memory” process. But we are accustomed to calling information also what the brain does not know how to remember. These are really existing objects of the world around us. This is all what we have to learn at school or college. It is this information that we will talk about now. Let's figure out how the brain reacts to real objects, to textual information, and to a very special type of information - symbolic (or precise) information. The brain cannot remember the listed types of information - real objects, texts, telephone numbers (and similar information). But experience suggests that we can still remember some of the above. How does memorization and reproduction of such information occur?

1. IMAGES 2. TEXT INFORMATION 3. SIGN INFORMATION

First, let's analyze the brain's reaction to real-life objects. How does the brain manage to reproduce them if none of the researchers can detect visual images in the brain? Nature acted very cunningly. Any really existing object has internal connections. The brain is able to identify and remember these connections. Have you ever wondered why a person actually needs several sense organs? Why are we able to smell, taste, see an object and hear it (if it emits sounds)? A real-life object emits physical and chemical signals into space. This is the light reflected from it or emitted by it, these are all sorts of vibrations in the air, an object can have a taste, and the molecules of this object can fly far from it. If a person had only one sense organ, then the brain’s memory system, which records connections, would not be able to remember anything. But one general information field from an object is divided by our brain into several components. Information enters the brain through different channels of perception. The visual analyzer conveys the outline of an object (let it be an apple). The auditory analyzer perceives sounds made by an object: when you bite into an apple, a characteristic crunch is heard. The taste analyzer perceives taste. The nose can detect molecules emitted by ripe apples from a few meters away. Some information about an object can enter the brain through the hands (touch). As a result of breaking information about an object into parts, the brain is able to form connections. And these connections are formed naturally. Everything that is in consciousness at one point in time is associated, that is, remembered. As a result, while we are studying an apple, while we are looking at it, twirling it in our hands, tasting it, the brain identifies different characteristics of this natural object and automatically forms connections between them. None of the characteristics by itself is remembered. Only connections are remembered. Later, when our nose smells the smell of apples - that is, a stimulus arrives at the brain - the previously formed connections will work and the brain will create other characteristics of this object in our minds. We will remember the whole image of an apple. The mechanism of natural memorization is so obvious that it’s even strange to talk about it. This method of memorization gives us the opportunity to RECOGNIZE the objects of the world around us only from a small part of the information about them.

Human perception of information

04.04.2015

Snezhana Ivanova

Perception is the process of reflection in the consciousness of a person of phenomena and objects in the sum of their properties, states, and components.

It is difficult to imagine the life of a modern person without information. The media are literally replete with all kinds of events that may interest a person. Today there is no shortage of information in any area; on the contrary, there is an excess of it. People often get confused about the same concepts because there may be conflicting information about the same subject. Therefore, in order to understand a complex issue, sometimes you have to study a bunch of different positions.

Perception– this is the process of reflection in the consciousness of the individual of phenomena and objects in the sum of their properties, states, components. This process is closely related to the senses, since we receive any information through the participation of visual, auditory and other sensations.

Process of information perception represents a highly organized internal work in which all mental processes participate: attention, imagination, memory, thinking. In order for the information entering the brain to be better absorbed, it must be realized or comprehended. Perception performs the function of a kind of conductor between new information and its awareness.

Human perception of information occurs at several levels. All of them, in one way or another, affect the senses and are associated with cognitive processes.

Channels of information perception

Under channels of perception understand the predominant orientation towards one sense organ, which ensures better assimilation of incoming information. It is worth considering the factor that each person has his own individual orientation. For some, it is enough to read the material once to master it, for others it is necessary to listen to a lecturer on the same topic, etc.

• Visual channel. Aimed at assimilation of information by focusing more on visual images. A person who is dominated by this channel of perception has a high ability to absorb information through reading. In this case, it is enough for the individual to read the material, and the information will be firmly “fixed” in the brain. There is no need to retell what you read or share with others. If the information itself is contradictory, raises additional questions, or provokes a dispute, then the individual may need to familiarize himself in detail with different opinions in order to form his own point of view.
• Auditory channel. Aimed at assimilating information by concentrating primarily on auditory images. If this channel of perception predominates, a person has a high ability to remember through listening to the desired material. Students whose auditory channel dominates perfectly absorb the proposed information during a lecture and don’t have to study anything at home - everything is already easy in their head, so there are no unnecessary questions left! If difficult moments arise, the material is complex and incomprehensible, such a person usually strives to immediately clarify important details and figure it out on the spot by asking the lecturer the appropriate questions.
• Kinesthetic channel. Aimed at assimilation of information by focusing primarily on physical sensations. Kinesthetic perception is closely related to the organs of touch, so such a person must touch the interlocutor during a conversation. Smell and taste are also of paramount importance for this person - she is most attentive to details and her own feelings. If you ask a person what is happening to him, he will be able to describe his emotions in colors and recognize their true manifestations.
• Digital channel. Aimed at assimilation of information by concentrating on abstract - logical images. Such a person is inclined to look for meaning in everything, to sort his knowledge “on shelves.” It is extremely important for a digital person to know for what purpose he performs this or that action and what will follow from it. He has the ability to predict the situation, and therefore is prone to planning and in-depth analysis of current events. Most often, digital people are engaged in scientific activities throughout their lives.

The listed channels of perception are leading, but besides them there are others: gustatory, olfactory, semantic, etc. In accordance with the presented features of each channel, psychology distinguishes the following types of information perception: visual, auditory, tactile, verbal. Each of the listed types is fully correlated with the above-mentioned channels of information perception.

Properties of perception

• Objectivity. Characterized by a focus on the outside world. A person always focuses his attention on things that are reflected in the surrounding space. These may not necessarily be objects and phenomena, but also abstract concepts. In any case, there is deep mental concentration on one or another subject: everyday, artistic or scientific.
• Integrity. Unlike sensation, which reflects individual properties of objects and phenomena of the surrounding world, perception constitutes its general image. It consists of a combination of different sensations and forms a holistic idea of ​​a particular object.
• Structurality. It should be noted that human perception is structured in such a way that it has the ability to systematize material in a certain order, that is, from the general flow of incoming information, select only that which will be useful in a given case.
• Constancy. This property refers to the relative constancy of perceived information under different conditions. For example, the shapes of objects, their size, and color appear the same to a person under different living conditions.
• Meaningfulness. A person not only perceives objects and phenomena, he does it meaningfully, purposefully, anticipating a certain result and striving for it. For example, students listen to a lecture in order to pass a test or exam more successfully, and attend classes on artistic culture for self-education. In every action, a person strives to act meaningfully, because otherwise no activity can be performed.

Complex forms of information perception

Forms of information perception are understood to be certain categories that are based on reflection and a focus on searching for truth.

• Perception of space. Each of us has a very individual approach to the perception of space. If we are transferred to another place, we will not be able to immediately find our way until we develop behavioral tactics and understand how best to behave. One person is able to navigate changing conditions differently than another and everyone has their own perception.
• Perception of time. Each of us has our own biological clock that reminds us to take certain actions. There is a common theory about night owls and early risers. Some find it difficult to wake up in the morning; they may stay awake during the day; others need to get up early and go to bed early. If you ask a person on the street with the question “What time is it?”, most will immediately start looking for a watch to answer you. Meanwhile, inside everyone knows approximately what time it is at the moment. This is why the process of planning any business, predicting various situations even before they happen in reality, becomes possible.
• Perception of movement. Impressions of movement are created purely individually. It is enough for someone to tilt their head forward and take the appropriate position of their body to create the illusion that they are moving in space. The perception of movement is recorded by the brain and realized by the individual through the vestibular apparatus and one’s own thoughts and subjective moods.
• Perception is intentional and unintentional. These forms differ from each other in the participation of consciousness in the perception of any objects. Otherwise, they can also be called involuntary and voluntary. In the first case, perception is carried out due to external circumstances that attracted a person’s attention, and in the second, it is guided by consciousness. Intentional perception is characterized by a clear goal, defined tasks, a clear structure and consistency in the implementation of all necessary steps.

Peculiarities of information perception

Each person approaches the perception of the same events and phenomena very individually. After all, one will see a blessing for himself in what is happening, while the other will consider it a punishment for himself in these circumstances. In addition, people also differ in the leading channels of information perception. If someone needs to read the material being studied, then it is very important for another to listen to it by ear.

For the visual it is extremely important that all information is within his field of vision. It is great if you have the opportunity to become familiar with the material through reading. Only when the visual sees what it looks like that he needs to remember, he is able to truly perceive.

For auditory It is always better to hear the material once than to read it several times. This is the type of perception when a word spoken live acquires enormous significance. People who have a leading auditory channel of perception always find it easier to absorb information in lectures or participate in seminars.

A distinctive feature of kinesthetics There is a natural need to touch everything with your hands. Otherwise, the process of holistic perception cannot proceed. Only with the help of emotions, reinforced by interaction with people or objects, do they understand the surrounding reality. As a rule, such people are very emotional and exposed to various areas of activity. Quite a lot of them are artists, musicians, sculptors, that is, they include those who are able to live their whole lives in contact with objects and even create their own reality.

Digitals are inclined to a deep analysis of current events. These are essentially true thinkers and philosophers. For them, new information must necessarily be the subject of abstract analytical thinking, the fruit of serious internal work associated with the logical alignment of complex structures. To know the truth is their main goal.

Thus, there are very different ways of perceiving information. Together they create a harmonious and holistic picture of the world, in which the fullness of diversity is welcomed. It is necessary to develop all channels of perception, but do this based on the leading view. Then any human activity will be successful and will lead him to new discoveries and achievements.

A team of scientists from Spain, France and England announced the completion of the first ever experiment on transmitting a signal between the minds of two people using exclusively non-invasive technologies. A signal consisting of 140 bits of information was transmitted from India to France via the Internet. The work was published in PLOS One.

General scheme of the experiment. Image: PLOS one article

The experiment was based on brain-computer interfaces (BCI) and computer-brain interfaces (CBI), the signal was transmitted via the Internet. The message was ultimately the word "hola" - "hello" in Spanish (and Catalan). The Bacon cipher, which uses 5 bits per letter, was used for encoding. The word was transmitted 7 times to collect sufficient statistics, so the final message was 140 bits long.

The scientists modeled the brain-computer interface as follows: to encode “0,” the human “transmitter” moved his foot, and to encode “1,” he moved his palm. By taking an electroencephalogram from the areas of the cerebral cortex responsible for these movements, the computer received the transmitted message in the form of binary bits.

With the computer-brain interface, things were more complicated. On the head of the human “receiver” they found the visual center of the cerebral cortex, upon stimulation of which the phenomenon of phosphenes arose - visual sensations that arise without information from the eye. The presence of such a feeling was coded “1”, the absence - “0”.

Four volunteers aged 28-50 years acted as transmitters and receivers. For the final experiment, the signal was transmitted from India to France. In order to eliminate interference from the senses, the “receiver” person was wearing a light-proof mask over his eyes, and plugs were placed in his ears. To eliminate the possibility of guessing the encoded word, the sequence was first further encoded to obtain a pseudo-random code, which, after transmission, was decrypted to restore the original message.

As a result of the experiment, it was possible to transmit 140 bits of information with an error rate of 4%. For comparison, to make sure that this result is statistically significant: the probability of guessing all 140 characters in a row is less than 10 -22 , and to guess at least 80% of 140 characters is less than 10 -13 . Thus, according to scientists, there actually was a direct transmission of the signal from brain to brain.

The novelty and significance of this work stem from the fact that until now all such experiments were either limited to one of two interfaces, or were carried out on laboratory animals, or involved invasive procedures for implanting sensors into a living organism. In this work, scientists for the first time managed to realize non-invasive transmission from person to person.