Why does the rabbit not have a diencephalon? Brain and spinal cord of rabbits. What are rabbits afraid of? Peripheral nervous system

The progress of neuropsychiatry in the last two decades has determined a peculiar leap in the development of brain stimulation techniques, the emergence of new methods and the improvement of old ones. Based on the idea of ​​the functioning brain as a kind of electrochemical organ, its stimulation can indirectly have a therapeutic effect, correcting pathologically altered functional activity. Traditionally, the “therapeutic niche” of non-drug methods has been located where the use of pharmacotherapy is limited by ineffectiveness or poor tolerability. At the same time, recent scientific advances regarding the neurobiology of mental disorders, as well as improvements in the technology of brain stimulation devices, may change the principles of treatment, expanding the clinical indications for the use of brain stimulation methods. Methods of brain stimulation include electroconvulsive therapy (ECT) and a number of new techniques, the development and implementation of which occurs in two fundamentally different directions:

■ The first includes methods that are safer in comparison with ECT and that provide local stimulation: transcranial magnetic stimulation, direct brain stimulation, alpha stimulation.

■ the second direction includes high-tech invasive methods that are being developed by neurosurgeons and psychiatrists: vagal stimulation, deep brain stimulation.

More information about ECT You can read, as well as in the book “Electroconvulsive therapy in psychiatry, addiction and neurology” by A.I. Nelson (Moscow, publishing house "BINOM. Laboratory of Knowledge", 2005) [read]; and in methodological recommendations"Carrying out electroconvulsive therapy in outpatient practice» (Ministry of Health under the Government of the Stavropol Territory, Stavropol Regional Clinical mental hospital No. 1, 2006) [read].

Transcranial magnetic stimulation() - a method of influencing the brain with magnetic pulses of various frequencies. Magnetic pulses in brain tissue form local electrical inductive currents, which in turn cause depolarization of neurons. High ability of magnetic field to penetrate through skin And bone tissue compared with electric shock allows you to more accurately dose the intensity. Another advantage of the technique is the relatively narrow focus of the effect, providing stimulation of local brain structures. Focal stimulation is achieved using a specially configured inductor coil (shaped like the number “8”). For more precise targeting of TMS, including in accordance with the results of EEG, MRI, PET or MEEG, neuronavigation compatible with a magnetic stimulator is used. IN last years Several studies have been conducted using coils that provide effects on deep brain structures (“theta-burst TMS”). In addition, TMS machines are used to provide magnetic convulsive therapy (MCT). In this case, magnetic pulses of higher frequency and intensity are used. Two small comparative studies found no definite differences in clinical effect MCT and ECT with a significantly better safety profile of magnetic convulsive therapy. Finally, TMS is a well-known diagnostic and research tool. First of all, it is used to determine the conductivity of motor pathways, as well as in studies of brain functioning when combining TMS with PET (positron emission tomography) and functional MRI. There are two fundamentally different methods of magnetic stimulation: cyclic (cTMS) and low-frequency or pulsed TMS. Using the cyclic technique, stimulation is carried out in cycles or trains, with a frequency of 5 - 20 Hz, while low-frequency TMS is carried out at a frequency of 1 Hz. It is assumed that cTMS has a local stimulating effect on neuronal activity, while low-frequency TMS, by suppressing ipsilateral neuronal activity, stimulates the contralateral one. These hypothetical mechanisms, determined by various magnetic stimulation techniques, determine the choice of lateralization of the influence of a pulsed magnetic field. With cTMS, stimulation is applied to the projection of the left prefrontal cortex, and low-frequency TMS is applied to the projection of the right prefrontal cortex. A comparative analysis of two TMS techniques indicates a more powerful antidepressant effect of cyclic stimulation, while low-frequency TMS has a clearly expressed anti-anxiety effect. Interestingly, when using TMS with a high frequency (over 20 Hz), a temporary blocking of the functioning of a part of the brain (for example, a block of the speech center) can be observed. Over the past 15 years, an impressive amount of research has been conducted on the use of TMS for various mental and neurological diseases. However, most of them were done on small groups of patients at one clinical site. The main target for TMS is depression. Other potential therapeutic targets for TMS include its use in obsessive-compulsive disorder, post-traumatic stress disorder, stress disorder and others anxiety disorders, as well as in neurological pathologies (epilepsy, chronic pain syndrome, vestibulopathy). Perhaps the most interesting is the use of TMS in patients with schizophrenia. In particular, when treating verbal hallucinosis, low-frequency TMS is used on the projection speech center(Unfortunately, TMS is not effective for other psychotic symptoms).

Vagal stimulation(BC) is a technique of cyclic intermittent stimulation vagus nerve(n. vagus) low electric current. The vagus nerve is believed to be a modulator brain activity regulating to the greatest extent reticular formation, anterior ganglia, as well as the nucleus of the solitary tract (nucl. solitarius) and the double nucleus (nucl. ambigiuus). Vagal stimulation is carried out through 2 electrodes implanted in the left cervical region locally with the location of the vagus nerve bundle. The generator is controlled using a laptop computer, which can change the therapy mode and also temporarily stop stimulation, including by the patient himself. VS was initially used to treat intractable epilepsy, with some patients experiencing gradual, significant improvements in mood and anxiety. One of the latest long-term studies of VS revealed higher effectiveness of VS compared with “usual” therapy in patients with treatment-resistant depression. These data provided the basis for FDA approval of VS for the treatment of “chronic depression” as 4th line therapy. It is noteworthy that there is repeated evidence that prior efficacy of ECT is a predictor of the effect of VS. In recent years, the psychiatric community has ranked this method a more cautious position, justifying the need for additional research due to the lack of evidence.

More details about vagal stimulation in the article “ Modern methods somatic intervention in therapy neuropsychiatric disorders» K.Yu. Retyunsky (GOU VPO Ural State Medical Academy of Roszdrav, State Healthcare Institution SO Institute of Medical Cell Technologies, Yekaterinburg), 2009 [read].

Deep brain stimulation(GMS) is a stereotactic neurosurgical technique and represents long-term (constant) high-frequency electrical stimulation of deep brain structures, mainly the subthalamic nuclei. It was originally used to treat severe forms Parkinson's disease. To date, it is an effective and registered method of treating essential tremor, dystonia and intractable epilepsy. MRI and neurophysiological navigation during implantation of electrodes, as well as the use of individual stimulation parameters increase therapeutic effect. In psychiatry, DBS is used primarily in the treatment of resistant depression and resistant obsessive-compulsive disorder (i.e., severe compulsion in adults, where DBS can be used in combination with pharmacotherapy).

What is alpha stimulation? 1. article “Alpha wave stimulation: advantages and disadvantages” [read]; 2. article “Effectiveness of alpha stimulation in correcting emotional disorders of students” Urazaeva F.Kh., Urazaev K.F., Fedorova E.A., Urazaev D.K., Mannanov E.I., State Educational Institution of Higher Professional Education “Sterlitamak State Pedagogical Academy", Sterlitamak; magazine "Modern high technology» No. 11 2010 [read].

© Laesus De Liro

A team of scientists led by MIT graduate Robert McIntyre managed to freeze the brain of a small mammal and restore it to a state close to ideal. The Brain Preservation Foundation awarded the team the Small Mammal Brain Preservation Prize.

Scientists have been researching cryopreservation since the 17th century, when experiments first began on freezing animals that hibernated in winter. The English scientist John Hunter in the 18th century put forward theories about extending human life through cyclic freezing and thawing. At the end of the 19th and beginning of the 20th century, Russian physicist and biologist Porfiry Ivanovich Bakhmetyev studied the phenomena of suspended animation and hypothermia in animals. He developed a thermoelectric thermometer for measuring temperature in insects and showed that recovery from suspended animation is possible if tissue fluids remain in a liquid state.

A person was cryopreserved for the first time in 1967. It was psychology professor James Bedford, who was dying of kidney cancer with metastases to the lungs. In 2010, experiments to create cryosleep technology for soldiers began by DARPA.

In 2015, Natasha Vitamore from the American University of Modern Technologies and Daniel Barranco from the cryobiotechnology department of the Spanish University of Seville, that the use of cryonics technologies does not destroy the long-term memory of the simplest multicellular organisms - in in this case we were talking about nematode worms Caenorhabditis elegans.

In the worm Caenorhabditis elegans, the nervous system consists of 302 cells. And the human brain contains 86 billion neurons, making it difficult for scientists to preserve it. Cryopreservation should preserve long-term memory so that the brain can then be restored or loaded into a machine.

In order to achieve the ability to preserve the human brain, scientists are experimenting with other mammals. In 1995, biologist Yuri Pichugin froze sections of a rabbit's brain; after thawing, the sections were preserved bioelectrical activity. In a new study from an MIT graduate, scientists cryopreserved an entire rabbit brain and then restored it with minimal damage.

The technology proposed by a team of 21 Century Medicine scientists showed that the cryoprotectant is able to protect against the formation of ice crystals even when the brain temperature slowly drops to minus 130 degrees Celsius. The team was able to save neural connections after defrosting my brain. Scientists filled brain vessels with special chemicals, which recorded the neurons, cooled the brain, and then warmed it up and removed these substances.

"Every neuron and synapse appears beautifully preserved throughout the brain," says neuroscientist Kenneth Hayworth, president of the Brain Preservation Foundation, which awarded the prize. Foundation judges verified this using electron microscopy. Foundation co-founder John Smart told Motherboard that for the first time, the procedure preserved everything that neuroscientists believe is involved in learning and memory.

The brain of rabbits is covered with three membranes: hard, arachnoid and soft. Between the hard and arachnoid membranes there is a subdural space filled with cerebrospinal fluid (its outflow is possible in venous system and into the organs of lymph circulation), and between the arachnoid and soft - the subarachnoid space.

The brain of rabbits consists of white ( nerve fibers) and gray matter (neurons). The gray matter in it is located on the periphery of the cerebral cortex, and the white matter is in the center.
The brain of rabbits is the highest department of the nervous system of rabbits, controlling the activity of the entire organism, uniting and coordinating the functions of all internal organs and systems. With pathology of rabbits (trauma, tumor, inflammation), the functions of the entire brain of rabbits are disrupted, which is expressed in impaired movement, changes in the functioning of the internal organs of rabbits, disturbances in the behavior of rabbits, comatose(lack of animal response to the environment).
The spinal cord of rabbits is part of the central part of the nervous system, which is a cord of brain tissue with remnants of the brain cavity. It is located in spinal canal and starts from the medulla oblongata of the brain and ends in the region of the 7th lumbar vertebra. Its mass in a rabbit is 3.64 g.
The spinal cord of rabbits is conventionally divided without visible boundaries into the cervical, thoracic and lumbosacral regions, consisting of gray and white brain matter. In the gray matter there are a number of somatic nerve centers that carry out various unconditioned (innate) reflexes, for example, at the level of the lumbar segments there are centers that innervate the pelvic limbs and abdominal wall. The gray matter is located in the center of the spinal cord of rabbits and is shaped like the letter "H", while the white matter is located around the gray matter.
The spinal cord of rabbits is covered with three protective membranes: hard, arachnoid and soft, between which there are gaps filled with cerebrospinal fluid. Depending on the indications, veterinarians may inject this fluid and the subdural space into the fluid.
The peripheral part of the nervous system of rabbits is a topographically distinguished part of the unified nervous system, which is located outside the brain and spinal cord. It includes cranial and spinal nerves with their roots, plexuses, ganglia and nerve endings, embedded in rabbit organs and tissues. So, 31 pairs come off from the spinal cord of rabbits peripheral nerves, and from the head - only 12 pairs.
The autonomic nervous system of rabbits has special centers in the spinal cord and brain, as well as a number of nerve nodes located outside the spinal cord and brain.
Compared to other farm animals, rabbits are more timid. Rabbits are especially afraid of sudden strong sounds. Therefore, they must be handled more carefully than other animals.

The anatomy of rabbits has much in common with the internal structure of other mammals, but there are also fundamental differences. In this article we will figure out what the skeleton of a rabbit consists of, as well as how its vital organs are located.

The skeleton of a rabbit is similar in many ways to the skeletons of other mammals, but has distinctive features

Performs supporting and protective functions. It includes 212 bones. In an adult pet it takes up 10% of the body weight, in small rabbits – 15%. Cartilage, tendons and muscles bind bones together. It is divided into axial and peripheral.

Interestingly, meat breed rabbits have smaller skeletons than their fur breed counterparts..

Peripheral

Includes limb bones.

Divided into:

• Thoracic limbs (front legs). Represented by shoulder blades (belt), humerus, forearm, hand. The latter, in turn, consists of 9 short carpals, 5 metacarpals and 5 fingers consisting of phalanges (the first has 2 phalanges, the others - 3);
• Pelvic limbs (hind legs). Includes the pelvis, ilium, pubic and ischium, thighs, legs, feet, 3 phalanges of 4 fingers.

The collarbone connects the sternum and shoulder blades together, which allows rodents to jump. The bones of their legs are thin, hollow inside; rabbits are deprived of a strong spine. For these reasons, they often experience broken paws, and if they are careless, spinal injuries are possible.

The structural features of the skeleton allow it to jump to great heights

Axial

Includes major bones such as the skull and spine.

Structure:

• Skull (cerebral and facial sections). The bones are movable and connected with special sutures. IN brain section includes 7 bones (occipital, parietal, temporal and others). The facial includes the maxillary, nasal, lacrimal, zygomatic, palatine bone etc. The skull of a rabbit is elongated, similar in appearance to the skull of other mammals. Most of it (3\4) is occupied by the respiratory and digestive organs;
• Torso (vertebral column, sternum, ribs). Spinal column or the ridge consists of 5 parts, about which we'll talk below. The flexibility of the spine is given by the menisci, which hold the vertebrae together.

Wide vertebrae are characteristic of meaty breeds. Knowing this property helps breeders select the right species.

The cervical region includes 7 vertebrae. Thoracic region presented 12-13. They are held together by ribs, forming chest, where the heart and lungs are located. The number of vertebrae in the lumbar region varies from 6 to 7, in the sacral region their number is 4. The caudal region is represented by 15 vertebrae.

The rabbit skeleton contains 212 bones, wide vertebrae determine the meat breed

Muscular system

The taste of meat and the appearance of pets are determined by the muscular system. Under the influence of impulses, muscles tend to contract.

Types of muscles:

• Muscles of the body. Represented by striated muscle tissue. This includes all muscles;
• Musculature of internal organs. Consists of smooth muscle tissue. For example, the walls of the respiratory organs, digestive organs, and the walls of blood vessels.

The rabbits' lifestyle does not imply strong physical exercise As a result, their muscles are not sufficiently saturated with myoglobin and sarcoplasm. The meat has a white-pink tint; the color on the paws is darker than on the rest of the body. At birth muscular system babies are poorly developed, making up no more than 20% of the total weight. With age, this number increases to 40%.

The muscles of eared pets are not very rich in myoglobin, the meat is white-pink in color

I wonder what meat adult more calories than the meat of a small rabbit.

Nervous system

Divided into:

• Central (brain and spinal cord);
• Peripheral (nerves skeletal muscles, skin and blood vessels).

The brain is divided by a groove into 2 hemispheres (left and right), located inside the rabbit’s skull. Scientists conditionally divide it into the following sections (middle, posterior, oblong, etc.), each of them performs a separate function. For example, the oblongata is responsible for the respiratory and circulatory system.

The spinal cord is located in the spinal canal, which begins in the brain and ends in the seventh cervical vertebra. Weighs about 3.64 grams. Consists of gray matter, shaped like the letter “H”, and white matter, surrounding the gray.

The peripheral section usually includes the cranial and spinal nerves, nerve endings.

The rabbit spinal cord weighs 3.64 grams and consists of gray and white matter

The cardiovascular system

It includes everything that is in one way or another connected with blood: hematopoietic organs (spleen), lymphatic system, arteries, veins, capillaries, etc. Each of them performs its own specific function: the spleen, whose weight does not exceed 1.5 grams, regulates blood pressure. Bone marrow responsible for the production of red blood cells.

The thymus gland stimulates blood formation; its weight in newly born rabbits is only 2.3 grams; over time, this volume decreases.

Up to 280 ml of blood circulates in the body of a mammal. The body temperature of a healthy rodent in winter is 37 °C, in summer - 40-41 °C. When the temperature rises to 44 °C, the animal dies.

The anatomy of the rabbit heart has been studied for a long time; it is four-chambered, divided into 2 ventricles and 2 atria (chambers), weighs about 6.5 grams, and is located in the pericardial serous cavity. Normal heart rate is 110-160 beats per minute.

The heart of a rabbit weighing 6.5 grams has 4 chambers where up to 280 ml of blood circulates

Digestive system

With its help, the rabbit processes food, thereby prolonging its life. The foods he consumes pass through the gastrointestinal tract within 72 hours.

At birth, a baby rabbit has 16 teeth. After two and a half weeks of life, baby teeth are replaced by molars. In adult individuals there are 28 of them, in other mammals their number is larger. They grow constantly throughout life. Rabbits have large incisors with which they chew hard food; With the molars located below, the baby grinds his food.

Rabbits have 2 incisors below and above for gnawing solid food.

Interestingly, rabbits do not have fangs.

Chewed food goes first into the pharynx, and then into the esophagus and stomach. The latter is a hollow organ, the volume of which reaches up to 200 cm3, it produces gastric juice. It must be said that the activity of the rabbit's gastric enzymes is higher compared to the enzymes of other animals. The fiber consumed by the eared animals is not digested here, and in an unprocessed form goes directly into the intestines, which completes the digestion process. It in turn is divided into:

• Small intestine . It breaks down substances, some of which (for example, amino acids) are sent directly into the blood;
• Colon. It is characterized by fermentation processes. Undigested and undigested food is excreted in the form of feces (up to 0.2 grams per day). Moreover, during the day it has a hard form, and at night it has a soft form. Individuals tend to eat the stool excreted at night; due to this property, the body is saturated with necessary proteins, vitamins B and K.

The rabbit's stomach digests food more actively than other mammals.

Respiratory system

The nose, pharynx, trachea, and lungs belong to the respiratory system. They provide the body with oxygen. During inhalation, the collected air is warmed, filled with moisture, and cleansed of contaminants in the nasal cavity. From there it goes into the pharynx, then into the trachea, and finally into the lungs.

It is important to know that rabbits breathe more often than other mammals. Normally, an individual takes 282 breaths per minute. They have a fairly active gas exchange: when they consume 478 cm3 of oxygen, 451 cm3 of carbon dioxide is released.

Furry pets breathe more often than other mammals; they normally take 282 breaths per minute.

Sense organs

Babies have developed the following sense organs:

• Smell. It is carried out by receptor cells located deep in the nasal cavity. On their surface there are 10 to 12 hairs that react to different aromas. With its help, a female rabbit can find her baby among strangers, easily find food, choose a male for mating, etc.;
• Taste . It is carried out thanks to taste buds located on the tongue;
• Touch. Implemented using sensitive skin in the area of ​​the eyelids, lips, back and forehead. It helps pets navigate in space, avoid temperature fluctuations, and respond to painful stimulation;

Rabbits have an excellent sense of smell, sensitive hearing and excellent vision even in the dark.

The antennae help animals move in complete darkness, and the hairs above the eyes tell them at what moment to duck to avoid a collision.

• Vision . Rabbits see the world in color. The animal's eye is eyeball spherical in shape, which directly connects to the brain. The peculiarity of the rabbits' vision is farsightedness and the ability to see in the dark;
• Rumor. A distinctive feature is the large ears, thanks to which the animals have sensitive hearing. Rabbits communicate with each other using high frequency sounds. To catch the necessary sound signals, animals turn their ears in different directions.

Genitourinary system

Presented by sexual and urinary organs. The latter remove waste products from the body. The volume of urine is directly proportional to the age and nutrition of the animal. Its daily norm does not exceed 400 ml. Myself urinary canal placed in close proximity to the reproductive apparatus.

Mammals have 2 kidneys oval shape. They take up space in the lumbar region and contribute to the breakdown of proteins, mineral salts and other substances. Urine is formed continuously, it travels from the kidneys to the ureters, then to bladder, which accumulates liquid for some time, and then reflexively removes it out. Normally it has a straw-yellow tint. Bright yellow or even brown color is a sign of disease.

Genitals

The reproductive organs of males and females are different. In the former, the reproductive apparatus is represented by paired testes, the vas deferens, accessory glands, and the penis. The uterus, ovaries, oviduct, vagina and genital opening make up reproductive system females The eggs mature in the ovaries and are released into the oviducts during ovulation. The shape of the uterus is bicornuate. Ovulation occurs 10-12 hours after intercourse.

The peculiarity of the rabbit's uterus is that it consists of two horns

Endocrine glands

They belong to thyroid, pituitary gland, pineal gland, adrenal glands, pancreas, testes and ovaries. Hormones enter directly into the blood because they do not have excretory pathways.

The adrenal glands regulate water and fat metabolism. The pituitary gland produces the most big number hormones and participates in many vital processes. If for some reason there are not enough glands in the body, this can lead to deviations in growth and development.

Summary

The rabbit skeleton diagram matches the description internal structure other mammals. Knowledge in this area allows owners farms properly care for your pets, recognize the disease in time, and, if necessary, contact a veterinarian to prescribe appropriate treatment.

Vertebrates.

Supreme trunk "tree of animals" form vertebrates animals. Man arose from one of the branches of this trunk. Only vertebrates have a nervous system similar in its main features to the human nervous system.

As a result of this anatomical similarity, mental similarities can also appear. In lower vertebrates, their mental similarity with humans is insignificant, but in mammals it grows as the mammal's brain approaches the human brain.

The central nervous system of vertebrates consists of the brain and spinal cord. In the ascending series of vertebrates, the brain reveals an increasingly developed structure, and each class of vertebrates has a brain of its own special structure and shape. For example, the brain of amphibians, or amphibians, is not as highly developed as the brain of reptiles, or reptiles; and the brain of birds turns out to be even more highly developed than the brain of reptiles. The brain of mammalian animals generally stands above the brain of reptiles, but within the group of mammals, in turn, there is a very significant increase in the degree of brain perfection when comparing the lower representatives of the group with the higher ones.

The stepwise sequence of increasingly developed forms of the mammalian brain thus marks a series of mental stages, which is why we must first begin to consider the structure of these anatomical forms. The brain of vertebrates consists of the following parts: 1) two hemispheres of the cerebrum, 2) the diencephalon, 3) the midbrain, 4) the cerebellum, 5) the medulla oblongata, or hindbrain.

Figure 6.1. Frog brain and fish brain

Rice. 7. Frog Brain
Rice. 8. Fish (trout) brain

From the hemispheres big The olfactory nerves originate from the brain. Big The brain of amphibians is not yet particularly large (Fig. 6.1, Fig. 7, g), in reptiles it is already much larger (Fig. 6.2), it is even larger in birds (Fig. 6.2) and it reaches its highest development in mammals ( Fig. 6.3).

From intermediate The optic nerves originate in the brain. The optic thalamus (Thalamus opticus) belongs to the diencephalon. In amphibians, the diencephalon lies behind the cerebrum (Fig. 6.1). But in reptiles and birds the cerebrum extends backward so far above the diencephalon that it completely covers the diencephalon, so that the latter is no longer visible from above (Fig. 6.2). Only a small outgrowth of the diencephalon, called the epiphysis, or superior medullary gland, remains visible.

Average the brain of most vertebrates forms two bulges (Fig. 6.1). In reptiles, these protuberances reach significant sizes (Fig. 6.2). In birds they are separated by the cerebellum (Fig. 6.2). In mammals, the midbrain is divided into four parts called quadrigeminal (Fig. 6.3, Fig. 11, m); in higher mammals this part is small and insignificant; the quadrigemina is covered from above by the large brain (Fig. 6.3).

Cerebellum in amphibians it is small (Fig. 6.1); in reptiles it is somewhat larger (Fig. 6.2); in birds (Fig. 6.2) and mammals (Fig. 6.3) it is already highly developed, since the flight of birds and the running of mammals require complex regulation by nerve centers localized in the cerebellum.

Rear the brain forms a continuation of the spinal cord, which is why it is designated as oblong brain (Fig. 6.1, Fig. 7, n). It departs from him to different sides a bunch of

It is not possible here to consider all the stages of gradual brain development in the vertebrate series.

The subject of our consideration will be only four classes: fish, amphibians, birds, mammals.

Fish.

Of the fish, we will consider only those that belong to the class of bony fish (Teleostei); this will include the most famous fish (carp, trout, pike, perch, etc.). The brain of these fish has some differences that are not present in the same form in lower fish (for example, sharks). The first section of the mammalian brain - the cerebrum - is relatively small here; its upper wall (Pallium) is very thin, while the midbrain is strikingly large (Fig. 6.1). The life of fish is regulated mainly by instincts, but along with them, many fish also have memory; from here we can see that the formation of pathways that develop during the process of individual life can occur not only in the upper wall of the cerebrum, but also in other parts of the brain. The existence of memory in fish has been proven by numerous experiments. Many fish living in aquariums can become tame and swim up to the person who brings them food. One gentleman in Mainz trained a rainbow trout so that it would take food from his hands, but after this man once pulled the fish out of the water for a second by its tail, the fish avoided approaching the food for three days. The ability of many fish to navigate in space has been established; so, for example, sticklebacks again find their nest in a space with a radius of 10 meters; some fish (pike, trout) return to " parking », where they lie in wait for prey, from quite significant distances (up to 6 kilometers). It has been repeatedly observed that fish in a pond remember the appearance of a person who regularly brings them food; so, for example, in one trout nursery, the watchman who brought food usually appeared in a bright red robe, and anyone who put on this clothing also managed to lure trout to him.

M. Ochsner produced with sea ​​fish(Coris julis, Serranus scriba) a number of experiments that undoubtedly prove the existence of memory in fish. He hung colorful cylinders in the aquarium and noticed that the fish were looking for food in the cylinder in which he had fed them before.

In a similar way, K. f.-Frisch found that the buffoon fish (Phoxinus laevis) can be trained to take food from a feeder of a certain color; it turned out, on the question of distinguishing colors, that although these fish do not clearly distinguish between red and yellow, however, they distinguish green from blue, as well as both of these latter colors from red and yellow, quite well.

Amphibians.

Moving from fish to amphibians, we see that their forebrain, diencephalon, midbrain and hindbrain are well developed, while the cerebellum is slightly developed (Fig. 6.1). The instincts of amphibians are localized in the forebrain only to a very small extent; the nerve centers with which they are connected are located mainly in the following parts of the brain and in the spinal cord. If you cut out the forebrain of a frog, then most of its vital functions are preserved, according to the physiologist Schrader. Animals operated in this way eat on their own, with the onset of winter they plunge into the silt at the bottom of the reservoir, and with the arrival of spring they come to the surface and mate. « “I am not able,” wrote the said scientist, “by simple observation to distinguish between normal and operated frogs living in the frog pond of the Physiological Institute - frogs that have been deprived of the forebrain and have completely recovered after the operation; the latter are revealed only by a thin line of scar on the scalp or a noticeable defect in the skull cap. A frog lacking a forebrain swims, jumps, and runs with the same agility as a normal individual, and it is amazingly good at orienting itself in space using the sense of vision» .

Compared with instincts, memory plays only a slightly noticeable role in amphibians: memory is not completely absent from them - as anyone who keeps a tree frog in captivity can easily see - but this memory is so insignificant that I will not dwell on it here .

Birds.

But in birds, memory plays a big role; memory is localized in birds mainly in the forebrain. If the forebrain of a pigeon or other bird is cut out (without damaging the diencephalon with optic nerves), then the animal becomes "mentally blind", i.e. it loses its understanding of objects in the outside world.

Figure 6.2. Reptile brain and bird brain

Rice. 9. Reptile (crocodile) brain
Rice. 10. Brain of a bird (pigeon)

The operated bird, however, perfectly retains the ability to run and flies without difficulty to its usual resting place, but it no longer recognizes the objects that this bird sees. « She makes no distinction whether what is reflected on the retina of her eye is some inanimate object, or a dog, a cat, a bird of prey, or the net with which she was caught; For an operated bird, all these objects are just obstacles that it tries to get around, that it wants to climb over, or that it wants to use as a place to rest during flights.» .

A pigeon without a forebrain allows itself to be caught without taking flight; a falcon without a forebrain allows itself to be captured without defending itself. During the mating season, a pigeon without a forebrain follows its instinct, coos diligently and exhibits all the movements of the courting male, but the female is not perceived by him as such, and he remains completely indifferent towards her.

« Just as the operated male no longer shows any interest in the female, so the operated female is not interested in her cubs; barely fledged chicks pursue their mother with incessant cries, and the effect is the same as if they were turning to a stone» .

Pigeons and chickens without a forebrain stop noticing their food and may starve to death on a pile of grain; To keep them alive, you need to put grains in their beaks. Here it is appropriate to recall the fact mentioned above, namely: chickens, through individual experience, learn to recognize food suitable for them. Thus, in the process of eating, recalled impressions associated with neural pathways that arose in individual life and pass through the forebrain are revived. With the removal of the forebrain, these memory images also disappear.

From the observations of Max Schrader, one can especially clearly see how, in the process of eating birds of prey, instinctive impulses and individually acquired experience interact. Schrader took young, fledgling falcons from the nest. When the falcons were shown a moving mouse, they immediately stretched out their paws to the prey, screaming loudly, and clung tightly to it with their claws, although the chicks were still completely unable to cause any harm to the mouse; they never even made an attempt to peck the prey, and they still had to be fed by hand; a piece of horse meat, a piece of a handkerchief, a human finger met the same reception. Thus, the reasons for grasping are apparently given by a moving body. IN normal conditions falcon chicks are fed by their parents, who give them live prey and gradually teach the chicks to recognize it. But in this case, this did not occur in the experimental chicks; They were given only horse meat and later dead pigeons for food. « When they were fully fledged, live prey was again allowed into their cage - white mice; It was interesting to observe how the falcons first observed the alien mice from a distance, and then began to carefully move closer and walk around the calmly gnawing mice, examining them from all sides; some chicks then moved away again and sat on the perch; one chick fearfully extended his paw to the mouse, but barely touched it when he quickly pulled his paw back; the mouse jumped to the side, the falcon ran far away, into more fear than a mouse. The experiment was repeated, the falcons became more and more bold, but only two or three days later the mice were caught and eaten by the falcons» . From this description it is clear that although falconers had an innate attraction to grasping living prey, they only learned through experience that mice are prey that can be grabbed and eaten.

Mammals.

Since we have already talked enough about the instincts and intelligence of birds in other places in this book, we will now move on to mammals animals.

Three parts of the brain are particularly developed in mammals: the forebrain, the cerebellum and the hindbrain. The diencephalon, on the other hand, is buried beneath the forebrain and can only be seen from the outside from the underside of the brain. The midbrain, which forms the quadrigeminal, loses its significance; in lower mammals it can still be seen behind the forebrain (Fig. 11). In higher mammals, the midbrain is so small that it is completely covered on top by the overgrown forebrain (Fig. 12).

We must pay attention to the forebrain Special attention, since it is the main seat of memory and reason. The largest part of the neural connections formed in individual life passes through the forebrain. When the forebrain is removed, all those manifestations on the basis of which one can conclude about the presence of memory, intelligence and reflection are lost.

Figure 6.3. Rabbit brain and dog brain

Rice. 11. Rabbit Brain
Rice. 12. Dog Brain

A dog with an excised forebrain, just like a pigeon with an excised forebrain, turns out to be "mentally blind", i.e. she does not notice either the water trough or the threat of a whip, she does not even recognize the cat placed in front of her. This dog does not react to either affectionate or rude words and remains indifferent even when petted, since its psychic connections with the people around it have disappeared. But such a dog can still for a long time to stay alive, since she is able to eat and drink, and most of her reflexes are preserved.

In lower mammals, the forebrain is relatively small and does not yet have convolutions. Thus, in insectivores, bats and most marsupials, the surface of the brain appears smooth, and the same is true in most rodents. But in higher mammals, the cerebral cortex increases in size, and deepening convolutions appear on it. All carnivorous animals and all ungulates have a convoluted cerebral cortex, as do seals, dolphins and whales. Of the monkeys, the lower breeds have few convolutions, while the higher monkeys have a more complex system of convolutions.

By the appearance of the convolutions of the brain, i.e. By the type of branching and the direction of the convolutions of the cerebral cortex, anthropoid (anthropoid) apes are closest to humans. In the genus of gibbons (Holobates), only the main grooves can be seen, but in chimpanzees, orang-utangs and gorillas there are already a complex system convolutions, very similar to those of humans. As for the mass of the brain and, consequently, its weight, here we observe big differences. The chimpanzee brain weighs 350 - 400 grams, the gorilla brain weighs about 425 grams, while the weight of the human brain in lower races is 900 - 1,000 grams, and in higher races it reaches 1,300 - 1,500 grams. and more.

In this case, you should also pay attention to the thickness of the cerebral cortex and the number nerve cells. There are mammals in which nerve cells are arranged in layers far apart from one another. These animals have 5,000 - 10,000 cells per cubic meter. mm. Marsupials, edentates, ruminants, elephants and whales have such a brain. Then we find a closer arrangement of cells in predators and seals: from 15,000 - 20,000 cells per cubic meter. mm. Rodents, prosimians and monkeys have the closest arrangement of cells: 35,000 - 50,000 per cubic meter. mm. A person has a very close arrangement of nerve cells. The high degree of intelligence inherent in humans is thus explained by the size of the forebrain, the complexity of the system of convolutions - which results in an increase in the area of ​​the cortex - and the close arrangement of cells in the cerebral cortex - therefore, the presence more neurons.

In zoology, the class of mammals is divided into three subclasses: cloacal (monotremata), (platypus and echidna), marsupials (marsupialia), placentals (placentalia), and marsupials are divided into several orders, and placentals into even more. larger number orders (e.g. edentates, insectivores, rodents, ungulates, cetaceans, carnivores, seals, the bats, prosimians and monkeys). But, from a zoopsychological point of view, it is advisable to combine into one group all those mammals whose brain structure retains features of a primitive type; and, on the other hand, a group of higher mammals with a brain of a more complex structure should be separately identified.

We find a primitive type of brain in cloacal and marsupials, and among placental animals - in rodents, insectivores and edentates. Their forebrain has not yet reached significant development; most often it does not yet cover the midbrain (quadrigeminal) (Fig. 11). On bottom side the forebrain has wide olfactory lobes, from which highly developed olfactory nerves arise; a significant part of the forebrain is thus occupied by the olfactory lobes. The surface of the forebrain cortex is smooth, has no convolutions, and the cerebral cortex has not yet achieved significant development. Mentally, these animals are not high, but their instincts have reached great perfection, for these animals are capable of producing amazing structures (recall, for example, the buildings of beavers, nests of hazel dormouse and squirrels, underground burrows of moles, hamsters, etc.).

The poor development of the mental abilities of these mammals is also reflected in the fact that very little can be achieved by training them; trained hedgehogs, rats or rabbits are never shown. But still, these animals have a memory for places and also a general ability to remember. Therefore, they are easy to tame. In Trieste, I saw a hedgehog in one restaurant, which in the evening constantly ran among the customers and allowed itself to be fed. I myself had a young hedgehog living in my apartment, who was released from his box in the evening, and who then began to run animatedly around the room and ate from his hands. For my experiments on the hereditary transmission of traits, I have been keeping an almost tame race of rats for many years; when rats grow up in a box so that no one touches them, they are afraid of people and do not like to be handled; If you pick up rats from a very early age, they become so tamed that I could let my children play with them.

We now come to those mammals whose brains appear furrowed with convolutions and whose cerebral cortex appears to be well developed. Thus, we approach the highest levels of animal mental activity. winding cerebral cortex possessed by predators (Fig. 12), seals, ungulates, cetaceans (dolphins and whales), as well as monkeys. In each of these orders of animals there is a special type of arrangement of gyri, which indicates that the gyri arose in each order independently, i.e. that in the order of phylogenetic development in each of these orders there were originally forms with a brain without convolutions. In the phylogenetic series of primates one can still see, as it were, a series of different stages of development: prosimians have, for the most part, a brain devoid of convolutions; in the brain of lower monkeys (for example, in the marmoset monkey - Hapale leoninus) the first traces of convolutions are just emerging; from these forms there is an increasing complexity of the grooves up to the well-developed system of convolutions of the brain of apes; the brain of these latter already has a very close resemblance to the human brain.

All those mammals that have had a reputation for being intelligent since ancient times, such as the elephant, horse, dog, fox and most monkeys, as well as all those animals in which, through training, it is possible to achieve significant results(dogs, lions, horses, elephants, sea lions and monkeys) all have highly convoluted forebrains. We have already mentioned the manifestation of the mind of anthropomorphic monkeys. Using the new method of knocking, it was found out even more precisely how highly developed psychic abilities are in horses and dogs. This has already been discussed above, and therefore there is no need for me to dwell here again on the mind of mammals.

It should only be mentioned that in relation to the instinctive feelings of mammals it is permissible to use the same terms that we apply to humans. So, for example, when we're talking about about a dog, we can talk about joy or sadness, about sympathy or antipathy, about melancholy and jealousy, about fear and fear, about anger and hatred. This is what they usually say in everyday speech, and the analogies we noted in the structure of the human brain and higher animals also provide scientific justification for the said usage.

Exaggeration: in circuses, mice, rats, and rabbits are many times the performers of the most bizarre " rooms ». (Editor's note).