ABOUT THE PROJECT
Academician of the Russian Academy of Sciences, Professor Alexander Nikolaevich Konovalov
Dear friends!
It is with great professional pleasure that I present the result of many years of work on the creation of a multimedia three-dimensional Atlas of the Human Brain. This fundamental work is based on many years of research on the brain, conducted at the Research Institute of Neurosurgery. academician N.N. Burdenko - data of magnetic resonance and computed tomography, digital angiography, the results of anatomical studies, as well as data systematized in scientific publications and atlases of previous ones. Advanced computer technologies have made it possible to create a convenient interactive three-dimensional version of the Atlas.
The human brain is the most complex and most perfect structure created by nature and it is very difficult to comprehend the features of its structure. Therefore, knowledge of the anatomy of the central nervous system and, in particular, the brain, is the foundation for the successful work of not only us, neurosurgeons, but also scientists of many specialties.
Knowledge of anatomy is also the basis for the training of young specialists in the field of neurology and neurosurgery. This 3D Anatomical Atlas of the Human Central Nervous System is designed to help solve these problems.
I would like to emphasize that the volumetric reconstruction of the most important structures of the brain - the cerebral cortex, subcortical nuclei, the trunk, pathways, the ventricular system, veins and arteries, the spinal cord and cranial nerves, make it possible to form a complete spatial representation of the structure of the brain. This knowledge is important for all specialists studying diseases of the nervous system and, first of all, for neurosurgeons. The presented Atlas will be very useful not only for beginners, but also for their senior colleagues, who are wise with practical and life experience.
Academician of the Russian Academy of Sciences Alexander Nikolaevich Konovalov
ABOUT THE PROJECT
One of the priority areas of scientific and practical activities of the company "TOLIKETI" are developments in the field of virtualization of human neuroanatomy.
Three-dimensional computer software technologies allow a completely new look at the structure of the human central nervous system. The defining concept of three-dimensional reconstruction opens up endless possibilities in the study of the laws of building the organic world.
Publishing house "TOLIKETI" represented by Doctor of Medical Sciences, Head of the Department of Neurooncology of the Research Institute of Neurosurgery named after N.N. acad. N.N.Burdenko David Ilyich Pitskhelauri and the Scientific Design Studio "BRAIN.ERA" represented by Samborsky Dmitry Yaroslavovich, who performed work related to three-dimensional modeling and design of the project, with the financial support of the "International Foundation for the Development of Neurosurgery and Neurorehabilitation", developed a project to create a THREE-DIMENSIONAL ATLAS OF THE HUMAN CENTRAL NERVOUS SYSTEM.
The software part of the project was developed by programming specialists Denis Islamov and Pavel Loginov.
Native computer and magnetic resonance tomograms of an average person, data from anatomical studies, as well as information on the anatomy of the human central nervous system systematized in scientific publications of previous years were used as initial data.
The creation of the Atlas is the main component of the project for use in scientific, practical and educational purposes in neurosurgery, neurology and other related disciplines. This development is based on a unique material obtained in the course of a 10-year joint work of neurosurgeons and specialists in the field of three-dimensional software technologies.
The concept of a virtual neuroanatomical atlas
The virtual atlas of the human central nervous system is a three-dimensional software concept that combines, firstly, various types of information about the brain and, secondly, a set of methods for working with this information. Atlases of the central nervous system naturally allow the integration of geometric, physical, physiological information obtained from various sources, giving users the opportunity to work with the entire set of data at once. The volume of information stored in a neuroanatomical atlas can be colossal, and therefore the internal organization of work with information is an extremely important parameter of the atlas, no less important than the information about the brain itself.
The structure and functional connections of complex intracerebral structures have been worked out in detail: the hypothalamus, thalamus, amygdala complex, hippocampal formation, basal ganglia, cerebellum, reticular formation, cranial nerves, CNS pathways, etc.
The software includes a large number of interactive neuroanatomical reconstructions and additional options that expand the functionality of the product.
The concept of separating information into layers, which can be turned on and off depending on the task, allows you to manage huge amounts of information that are typical for biological objects.
At all stages of the creation of the Atlas, great attention was paid to the accuracy of the provided anatomical information, achieved by auditing expert studies.
The content is divided into 12 sections, which contain virtual neuroanatomical block preparations.
The choice of the optimal angle, the determination of a set of assembly elements, the virtual preparation of structures that overlap the field of view, and the division of the preparation into several nested scenes ensure maximum disclosure of the area of interest.
The original solutions for 3D reconstruction of biological objects developed in the project made it possible to create a unique virtual product for neurosurgical purposes.
To build the cerebral cortex, taking into account the internal course of the gyri, which is an extremely difficult task, a step-by-step extrusion method based on embedded MRI sections was used. This was a unique advantage of the training atlas.
Three-dimensional solutions of algorithms for the structure of vessels with a branching system, which is difficult from the point of view of three-dimensional modeling, were also found.
The construction of the cisterns required huge resources and a deep analysis of the adjacent structures that determine their shape.
The construction of conducting systems required the search for a solution for three-dimensional modeling of such complex organic objects as the fibrous systems of the CNS.
The system of animation modules made it possible to simulate the movement of signal impulses in 12 cranial nerves and the main functional systems of the CNS.
One of the practical useful features of the atlas is the possibility of its use as a neurosurgical simulator. By simulating the rotation and zooming of the virtual surgical field, in selected reconstructions, and identifying structures from different angles, the surgeon gains a unique navigation experience for use in real operating conditions.
The built-in stereo mode using special glasses and VR mode (virtual helmets and other devices) allow you to work with content in modern formats.
PROJECT DEVELOPMENT STAGES
INTERACTIVE OPERATIONAL NAVIGATOR
Based on the Atlas, it is planned to create an interactive operating navigator that operates on the basis of three-dimensional reconstructions of the main neurosurgical approaches. The access reconstruction selected by the user is synchronized with the position of the patient in a given angle, which allows the neurosurgeon to quickly determine anatomical landmarks in the changing surgical field.
The operation of the surgeon in the intraoperative mode of the navigator provides for the following functions: rotation, scaling, as well as content management with the ability to hide anatomical objects that overlap the surgical field.
The use of elements of augmented (added) reality - incision lines, contours of burr holes, markers critical for the patient's life, anatomical loci, etc. allows you to optimally plan the operation and visualize instructions for assistants who "open" the surgical field.
In the program mode, access reconstruction can be supplemented and refined with virtual content: features of the individual structure, reconstruction of the pathological focus (tumor, aneurysm, etc.) and dislocation of adjacent brain structures.
BANK OF VARIABILITY
The next important direction in the development of the project is the creation of a bank of variability of the anatomical structures of the CNS with an open filling architecture. Anatomical structures created on the basis of elements of individual three-dimensional reconstructions will allow us to evaluate the whole diversity of human neuroanatomy.
Individual virtual reconstructions, in addition to the intraoperative mode, can be used in preoperative planning and postoperative analysis.
The simulator atlas being developed aims to achieve a significantly higher level of realism with the possibility of simulating neurosurgical operations in virtual reality mode.
An important component of the simulator is the development of “dynamic methods” that evaluate changes in brain structures under certain influences, in particular, when using a retractor and other neurosurgical instruments.
PERSONALIZATION
The final stage of the project is the development and implementation of the atlas personalization method. Based on the diagnostic data of high-tech methods of CT, MRI, digital angiography, which converge to a virtual three-dimensional reconstruction of a particular patient, the method will allow planning real operations and developing tactics for surgical intervention.
The software of the virtual neuroanatomical simulator was developed under WINDOWS with subsequent creation of versions for iPad, iPhone and Android. The development provides for the possibility of a constant upgrade of the software through an Internet service.
SOCIO-TECHNOLOGICAL INSTITUTE OF MOSCOW STATE SERVICE UNIVERSITY
ANATOMY OF THE CENTRAL NERVOUS SYSTEM
(Tutorial)
O.O. Yakymenko
Moscow - 2002
The manual on the anatomy of the nervous system is intended for students of the Socio-Technological Institute of the Faculty of Psychology. The content includes the main issues related to the morphological organization of the nervous system. In addition to anatomical data on the structure of the nervous system, the work includes histological cytological characteristics of the nervous tissue. As well as questions of information about the growth and development of the nervous system from embryonic to late postnatal ontogenesis.
For clarity of the material presented in the text, illustrations are included. For independent work of students, a list of educational and scientific literature, as well as anatomical atlases is given.
Classical scientific data on the anatomy of the nervous system are the foundation for studying the neurophysiology of the brain. Knowledge of the morphological characteristics of the nervous system at each stage of ontogenesis is necessary for understanding the age-related dynamics of human behavior and psyche.
SECTION I. CYTOLOGICAL AND HISTOLOGICAL CHARACTERISTICS OF THE NERVOUS SYSTEM
General plan of the structure of the nervous system
The main function of the nervous system is to quickly and accurately transmit information, ensuring the relationship of the body with the outside world. Receptors respond to any signals from the external and internal environment, converting them into streams of nerve impulses that enter the central nervous system. Based on the analysis of the flow of nerve impulses, the brain forms an adequate response.
Together with the endocrine glands, the nervous system regulates the work of all organs. This regulation is carried out due to the fact that the spinal cord and brain are connected by nerves with all organs, bilateral connections. Signals about their functional state come from the organs to the central nervous system, and the nervous system, in turn, sends signals to the organs, correcting their functions and providing all life processes - movement, nutrition, excretion, and others. In addition, the nervous system provides coordination of the activities of cells, tissues, organs and organ systems, while the body functions as a whole.
The nervous system is the material basis of mental processes: attention, memory, speech, thinking, etc., with the help of which a person not only cognizes the environment, but can also actively change it.
Thus, the nervous system is that part of the living system that specializes in the transmission of information and in the integration of reactions in response to environmental influences.
Central and peripheral nervous system
The nervous system is topographically divided into the central nervous system, which includes the brain and spinal cord, and the peripheral, which consists of nerves and ganglia.
Nervous system
According to the functional classification, the nervous system is divided into somatic (parts of the nervous system that regulate the work of skeletal muscles) and autonomous (vegetative), which regulates the work of internal organs. The autonomic nervous system is divided into two divisions: sympathetic and parasympathetic.
Nervous system
somatic autonomous
sympathetic parasympathetic
Both the somatic and autonomic nervous systems include a central and peripheral divisions.
nervous tissue
The main tissue from which the nervous system is formed is nervous tissue. It differs from other types of tissue in that it lacks intercellular substance.
Nervous tissue is made up of two types of cells: neurons and glial cells. Neurons play a major role in providing all the functions of the central nervous system. Glial cells are of auxiliary importance, performing supporting, protective, trophic functions, etc. On average, the number of glial cells exceeds the number of neurons by a ratio of 10:1, respectively.
The shells of the brain are formed by connective tissue, and the cavities of the brain are formed by a special type of epithelial tissue (epindymal lining).
Neuron - structural and functional unit of the nervous system
The neuron has features common to all cells: it has a shell-plasmatic membrane, a nucleus and cytoplasm. The membrane is a three-layer structure containing lipid and protein components. In addition, there is a thin layer on the surface of the cell called the glycocalys. The plasma membrane regulates the exchange of substances between the cell and the environment. For a nerve cell, this is especially important, since the membrane regulates the movement of substances that are directly related to nerve signaling. The membrane also serves as the site of electrical activity underlying rapid neural signaling and the site of action for peptides and hormones. Finally, its sections form synapses - the place of contact of cells.
Each nerve cell has a nucleus that contains genetic material in the form of chromosomes. The nucleus performs two important functions - it controls the differentiation of the cell into its final form, determining the types of connections and regulates protein synthesis throughout the cell, controlling the growth and development of the cell.
In the cytoplasm of a neuron there are organelles (endoplasmic reticulum, Golgi apparatus, mitochondria, lysosomes, ribosomes, etc.).
Ribosomes synthesize proteins, some of which remain in the cell, the other part is intended for removal from the cell. In addition, ribosomes produce elements of the molecular apparatus for most cellular functions: enzymes, carrier proteins, receptors, membrane proteins, etc.
The endoplasmic reticulum is a system of channels and spaces surrounded by a membrane (large, flat, called cisterns, and small, called vesicles or vesicles). A smooth and rough endoplasmic reticulum is distinguished. The latter contains ribosomes
The function of the Golgi apparatus is to store, concentrate and package secretory proteins.
In addition to systems that produce and transport various substances, the cell has an internal digestive system, consisting of lysosomes that do not have a specific shape. They contain a variety of hydrolytic enzymes that break down and digest many compounds that occur both inside and outside the cell.
Mitochondria are the most complex cell organelle after the nucleus. Its function is the production and delivery of energy necessary for the vital activity of cells.
Most of the body's cells are able to absorb various sugars, while energy is either released or stored in the cell in the form of glycogen. However, nerve cells in the brain use only glucose, since all other substances are trapped by the blood-brain barrier. Most of them lack the ability to store glycogen, which increases their dependence on blood glucose and oxygen for energy. Therefore, nerve cells have the largest number of mitochondria.
The neuroplasm contains special-purpose organelles: microtubules and neurofilaments, which differ in size and structure. Neurofilaments are found only in nerve cells and represent the inner skeleton of the neuroplasm. Microtubules stretch along the axon along the internal cavities from the soma to the end of the axon. These organelles distribute biologically active substances (Fig. 1 A and B). Intracellular transport between the cell body and the processes extending from it can be retrograde - from the nerve endings to the cell body and orthograde - from the cell body to the endings.
Rice. 1 A. Internal structure of a neuron
A distinctive feature of neurons is the presence of mitochondria in the axon as an additional source of energy and neurofibrils. Adult neurons are incapable of dividing.
Each neuron has an extended central part of the body - the soma and processes - dendrites and an axon. The cell body is enclosed in a cell membrane and contains the nucleus and nucleolus, maintaining the integrity of the membranes of the cell body and its processes, which ensure the conduction of nerve impulses. In relation to the processes, the soma performs a trophic function, regulating the metabolism of the cell. Through dendrites (afferent processes) impulses arrive to the body of the nerve cell, and through axons (efferent processes) from the body of the nerve cell to other neurons or organs
Most of the dendrites (dendron - tree) are short, strongly branching processes. Their surface is significantly increased due to small outgrowths - spines. Axon (axis - process) is often a long, slightly branching process.
Each neuron has only one axon, the length of which can reach several tens of centimeters. Sometimes lateral processes - collaterals - depart from the axon. The endings of the axon, as a rule, branch and are called terminals. The place where the axon departs from the cell soma is called the axonal hillock.
Rice. 1 B. External structure of a neuron
There are several classifications of neurons based on different features: the shape of the soma, the number of processes, the functions and effects that a neuron has on other cells.
Depending on the shape of the soma, granular (ganglion) neurons are distinguished, in which the soma has a rounded shape; pyramidal neurons of different sizes - large and small pyramids; stellate neurons; spindle-shaped neurons (Fig. 2 A).
According to the number of processes, unipolar neurons are distinguished, having one process extending from the cell soma; pseudounipolar neurons (such neurons have a T-shaped branching process); bipolar neurons, which have one dendrite and one axon; and multipolar neurons, which have several dendrites and one axon (Fig. 2B).
Rice. 2. Classification of neurons according to the shape of the soma, according to the number of processes
Unipolar neurons are located in sensory nodes (for example, spinal, trigeminal) and are associated with such types of sensitivity as pain, temperature, tactile, pressure, vibration, etc.
These cells, although called unipolar, actually have two processes that fuse near the cell body.
Bipolar cells are characteristic of the visual, auditory and olfactory systems
Multipolar cells have a variety of body shapes - spindle-shaped, basket-shaped, stellate, pyramidal - small and large.
According to the functions performed, neurons are: afferent, efferent and intercalary (contact).
Afferent neurons are sensory (pseudo-unipolar), their somas are located outside the central nervous system in the ganglia (spinal or cranial). The shape of the soma is granular. Afferent neurons have one dendrite that fits to receptors (skin, muscles, tendons, etc.). Through dendrites, information about the properties of stimuli is transmitted to the soma of the neuron and along the axon to the central nervous system.
Efferent (motor) neurons regulate the work of effectors (muscles, glands, tissues, etc.). These are multipolar neurons, their somas are stellate or pyramidal in shape, lying in the spinal cord or brain or in the ganglia of the autonomic nervous system. Short, abundantly branching dendrites receive impulses from other neurons, and long axons extend beyond the central nervous system and, as part of the nerve, go to effectors (working organs), for example, to the skeletal muscle.
Intercalary neurons (interneurons, contact) make up the bulk of the brain. They carry out communication between afferent and efferent neurons, process information coming from receptors to the central nervous system. Basically, these are multipolar stellate neurons.
Among the intercalary neurons, there are neurons with long and short axons (Fig. 3 A, B).
As sensory neurons, the following are shown: a neuron, the process of which is part of the auditory fibers of the vestibulocochlear nerve (VIII pair), a neuron that responds to skin stimulation (SN). Interneurons are represented by amacrine (AMN) and bipolar (BN) retinal cells, olfactory bulb neuron (OBN), locus coeruleus neuron (PCN), pyramidal cell of the cerebral cortex (PN), and stellate neuron (SN) of the cerebellum. The motoneuron of the spinal cord is shown as a motor neuron.
Rice. 3 A. Classification of neurons according to their functions
Sensory neuron:
1 - bipolar, 2 - pseudo-bipolar, 3 - pseudo-unipolar, 4 - pyramidal cell, 5 - neuron of the spinal cord, 6 - neuron of n. ambiguus, 7 - neuron of the nucleus of the hypoglossal nerve. Sympathetic neurons: 8 - from the stellate ganglion, 9 - from the superior cervical ganglion, 10 - from the intermediolateral column of the lateral horn of the spinal cord. Parasympathetic neurons: 11 - from the node of the muscular plexus of the intestinal wall, 12 - from the dorsal nucleus of the vagus nerve, 13 - from the ciliary node.
According to the effect that neurons have on other cells, excitatory neurons and inhibitory neurons are distinguished. Excitatory neurons have an activating effect, increasing the excitability of the cells with which they are associated. Inhibitory neurons, on the contrary, reduce the excitability of cells, causing a depressant effect.
The space between neurons is filled with cells called neuroglia (the term glia means glue, the cells “glue” the components of the central nervous system into a single whole). Unlike neurons, neuroglial cells divide throughout a person's life. There are a lot of neuroglial cells; in some parts of the nervous system there are 10 times more of them than nerve cells. Macroglial cells and microglial cells are isolated (Fig. 4).
Four main types of glial cells.
A neuron surrounded by various glia elements
1 - macroglia astrocytes
2 - macroglia oligodendrocytes
3 - microglia macroglia
Rice. 4. Macroglial and microglial cells
Macroglia include astrocytes and oligodendrocytes. Astrocytes have many processes that radiate from the cell body in all directions, giving the appearance of a star. In the central nervous system, some processes terminate in a terminal stalk on the surface of blood vessels. Astrocytes lying in the white matter of the brain are called fibrous astrocytes due to the presence of many fibrils in the cytoplasm of their bodies and branches. In the gray matter, astrocytes contain fewer fibrils and are called protoplasmic astrocytes. They serve as a support for nerve cells, provide repair of nerves after damage, isolate and unite nerve fibers and endings, participate in metabolic processes that simulate the ionic composition, mediators. The assumptions that they are involved in the transport of substances from blood vessels to nerve cells and form part of the blood-brain barrier have now been rejected.
1. Oligodendrocytes are smaller than astrocytes, contain small nuclei, are more common in the white matter, and are responsible for the formation of myelin sheaths around long axons. They act as an insulator and increase the speed of nerve impulses along the processes. The myelin sheath is segmental, the space between the segments is called the node of Ranvier (Fig. 5). Each of its segments, as a rule, is formed by one oligodendrocyte (Schwann cell), which, becoming thinner, twists around the axon. The myelin sheath has a white color (white matter), since the composition of the membranes of oligodendrocytes includes a fat-like substance - myelin. Sometimes one glial cell, forming outgrowths, takes part in the formation of segments of several processes. It is assumed that oligodendrocytes carry out a complex metabolic exchange with nerve cells.
1 - oligodendrocyte, 2 - connection between the glial cell body and the myelin sheath, 4 - cytoplasm, 5 - plasma membrane, 6 - intercept of Ranvier, 7 - loop of the plasma membrane, 8 - mesaxon, 9 - scallop
Rice. 5A. Participation of the oligodendrocyte in the formation of the myelin sheath
Four stages of "envelopment" of the axon (2) by the Schwann cell (1) and its wrapping by several double layers of the membrane are presented, which, after compression, form a dense myelin sheath.
Rice. 5 B. Diagram of the formation of the myelin sheath.
The neuron's soma and dendrites are covered with thin sheaths that do not form myelin and constitute gray matter.
2. Microglia are represented by small cells capable of amoeboid locomotion. The function of microglia is to protect neurons from inflammation and infections (according to the mechanism of phagocytosis - the capture and digestion of genetically alien substances). Microglial cells deliver oxygen and glucose to neurons. In addition, they are part of the blood-brain barrier, which is formed by them and endothelial cells that form the walls of blood capillaries. The blood-brain barrier traps macromolecules, limiting their access to neurons.
Nerve fibers and nerves
Long processes of nerve cells are called nerve fibers. Through them, nerve impulses can be transmitted over long distances up to 1 meter.
The classification of nerve fibers is based on morphological and functional features.
Nerve fibers that have a myelin sheath are called myelinated (pulp), and fibers that do not have a myelin sheath are called unmyelinated (pulpless).
According to functional features, afferent (sensory) and efferent (motor) nerve fibers are distinguished.
Nerve fibers that extend beyond the nervous system form nerves. A nerve is a collection of nerve fibers. Each nerve has a sheath and blood supply (Fig. 6).
1 - common nerve trunk, 2 - branching of the nerve fiber, 3 - nerve sheath, 4 - bundles of nerve fibers, 5 - myelin sheath, 6 - Schwan cell membrane, 7 - Ranvier intercept, 8 - Schwan cell nucleus, 9 - axolemma.
Rice. 6 Structure of a nerve (A) and nerve fiber (B).
There are spinal nerves associated with the spinal cord (31 pairs) and cranial nerves (12 pairs) associated with the brain. Depending on the quantitative ratio of afferent and efferent fibers in one nerve, sensory, motor and mixed nerves are distinguished. In sensory nerves, afferent fibers predominate, in motor nerves - efferent fibers, in mixed ones - the quantitative ratio of afferent and efferent fibers is approximately equal. All spinal nerves are mixed nerves. Among the cranial nerves, there are three types of nerves listed above. I pair - olfactory nerves (sensory), II pair - optic nerves (sensory), III pair - oculomotor (motor), IV pair - trochlear nerves (motor), V pair - trigeminal nerves (mixed), VI pair - abducens nerves ( motor), VII pair - facial nerves (mixed), VIII pair - vestibulo-cochlear nerves (mixed), IX pair - glossopharyngeal nerves (mixed), X pair - vagus nerves (mixed), XI pair - accessory nerves (motor), XII pair - hypoglossal nerves (motor) (Fig. 7).
I - pair - olfactory nerves,
II - para-optic nerves,
III - para-oculomotor nerves,
IV - paratrochlear nerves,
V - pair - trigeminal nerves,
VI - para-abducens nerves,
VII - parafacial nerves,
VIII - para-cochlear nerves,
IX - para-glossopharyngeal nerves,
X - pair - vagus nerves,
XI - para-accessory nerves,
XII - pair-1,2,3,4 - roots of the upper spinal nerves.
Rice. 7, Diagram of location of cranial and spinal nerves
Gray and white matter of the nervous system
Fresh sections of the brain show that some structures are darker - this is the gray matter of the nervous system, while other structures are lighter - the white matter of the nervous system. The white matter of the nervous system is formed by myelinated nerve fibers, the gray matter is formed by unmyelinated parts of the neuron - soma and dendrites.
The white matter of the nervous system is represented by central tracts and peripheral nerves. The function of white matter is the transmission of information from receptors to the central nervous system and from one part of the nervous system to another.
The gray matter of the central nervous system is formed by the cerebellar cortex and the cortex of the cerebral hemispheres, nuclei, ganglia and some nerves.
The nuclei are accumulations of gray matter in the thickness of the white matter. They are located in different parts of the central nervous system: in the white matter of the cerebral hemispheres - subcortical nuclei, in the white matter of the cerebellum - cerebellar nuclei, some nuclei are located in the intermediate, middle and medulla oblongata. Most of the nuclei are nerve centers that regulate one or another function of the body.
Ganglia are a collection of neurons located outside the central nervous system. There are spinal, cranial ganglia and ganglia of the autonomic nervous system. Ganglia are formed mainly by afferent neurons, but they may include intercalary and efferent neurons.
Interaction of neurons
The place of functional interaction or contact of two cells (the place where one cell influences another cell) was called the synapse by the English physiologist C. Sherrington.
Synapses are either peripheral or central. An example of a peripheral synapse is the neuromuscular junction when a neuron makes contact with a muscle fiber. Synapses in the nervous system are called central when two neurons are in contact. Five types of synapses are distinguished, depending on which parts the neurons contact: 1) axo-dendritic (the axon of one cell contacts the dendrite of another); 2) axo-somatic (the axon of one cell contacts the soma of another cell); 3) axo-axonal (the axon of one cell contacts the axon of another cell); 4) dendro-dendritic (the dendrite of one cell is in contact with the dendrite of another cell); 5) somo-somatic (somes of two cells contact). The bulk of the contacts are axo-dendritic and axo-somatic.
Synaptic contacts can be between two excitatory neurons, two inhibitory neurons, or between excitatory and inhibitory neurons. In this case, the neurons that have an effect are called presynaptic, and the neurons that are affected are called postsynaptic. The presynaptic excitatory neuron increases the excitability of the postsynaptic neuron. In this case, the synapse is called excitatory. The presynaptic inhibitory neuron has the opposite effect - it reduces the excitability of the postsynaptic neuron. Such a synapse is called inhibitory. Each of the five types of central synapses has its own morphological features, although the general scheme of their structure is the same.
The structure of the synapse
Consider the structure of the synapse on the example of axo-somatic. The synapse consists of three parts: the presynaptic ending, the synaptic cleft and the postsynaptic membrane (Fig. 8 A, B).
A- Synaptic inputs of the neuron. Synaptic plaques of the endings of presynaptic axons form connections on the dendrites and body (some) of the postsynaptic neuron.
Rice. 8 A. The structure of synapses
The presynaptic ending is an extended part of the axon terminal. The synaptic cleft is the space between two contacting neurons. The diameter of the synaptic cleft is 10-20 nm. The membrane of the presynaptic ending facing the synaptic cleft is called the presynaptic membrane. The third part of the synapse is the postsynaptic membrane, which is located opposite the presynaptic membrane.
The presynaptic ending is filled with vesicles (vesicles) and mitochondria. Vesicles contain biologically active substances - mediators. Mediators are synthesized in the soma and transported via microtubules to the presynaptic ending. Most often, adrenaline, noradrenaline, acetylcholine, serotonin, gamma-aminobutyric acid (GABA), glycine and others act as a mediator. Usually, the synapse contains one of the mediators in a larger amount compared to other mediators. According to the type of mediator, it is customary to designate synapses: adrenoergic, cholinergic, serotonergic, etc.
The composition of the postsynaptic membrane includes special protein molecules - receptors that can attach molecules of mediators.
The synaptic cleft is filled with intercellular fluid, which contains enzymes that contribute to the destruction of neurotransmitters.
On one postsynaptic neuron there can be up to 20,000 synapses, some of which are excitatory, and some are inhibitory (Fig. 8 B).
B. Diagram of neurotransmitter release and processes occurring in a hypothetical central synapse.
Rice. 8 B. The structure of synapses
In addition to chemical synapses, in which mediators participate in the interaction of neurons, there are electrical synapses in the nervous system. In electrical synapses, the interaction of two neurons is carried out through biocurrents. Chemical stimuli predominate in the central nervous system.
In some interneurons, synapses, electrical and chemical transmission occurs simultaneously - this is a mixed type of synapses.
The influence of excitatory and inhibitory synapses on the excitability of the postsynaptic neuron is summed up and the effect depends on the location of the synapse. The closer the synapses are to the axonal hillock, the more efficient they are. On the contrary, the farther the synapses are located from the axonal hillock (for example, at the end of the dendrites), the less effective they are. Thus, synapses located on the soma and axonal hillock affect neuron excitability quickly and efficiently, while the effect of distant synapses is slow and smooth.
Neural networks
Thanks to synaptic connections, neurons are combined into functional units - neural networks. Neural networks can be formed by neurons located at a short distance. Such a neural network is called local. In addition, neurons remote from each other, from different areas of the brain, can be combined into a network. The highest level of organization of neuron connections reflects the connection of several areas of the central nervous system. This neural network is called through or system. There are descending and ascending paths. Information is transmitted along ascending pathways from the underlying areas of the brain to the overlying ones (for example, from the spinal cord to the cerebral cortex). Descending tracts connect the cerebral cortex with the spinal cord.
The most complex networks are called distribution systems. They are formed by neurons of different parts of the brain that control behavior, in which the body participates as a whole.
Some neural networks provide convergence (convergence) of impulses on a limited number of neurons. Neural networks can also be built according to the type of divergence (divergence). Such networks cause the transmission of information over considerable distances. In addition, neural networks provide integration (summation or generalization) of various kinds of information (Fig. 9).
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Rice. 9. Nervous tissue.
A large neuron with many dendrites receives information through synaptic contact with another neuron (upper left). The myelinated axon forms a synaptic contact with the third neuron (below). Neuronal surfaces are shown without glial cells that surround the process directed towards the capillary (upper right).
Reflex as the basic principle of the nervous system
One example of a neural network would be the reflex arc needed to carry out the reflex. THEM. Sechenov in 1863 in his work “Reflexes of the brain” developed the idea that the reflex is the basic principle of operation not only of the spinal cord, but also of the brain.
A reflex is a response of the body to irritation with the participation of the central nervous system. Each reflex has its own reflex arc - the path along which excitation passes from the receptor to the effector (executive organ). Any reflex arc consists of five components: 1) a receptor - a specialized cell designed to perceive a stimulus (sound, light, chemical, etc.), 2) an afferent path, which is represented by afferent neurons, 3) a section of the central nervous system , represented by the spinal cord or brain; 4) the efferent pathway consists of axons of efferent neurons that extend beyond the central nervous system; 5) effector - a working organ (muscle or gland, etc.).
The simplest reflex arc includes two neurons and is called monosynaptic (according to the number of synapses). A more complex reflex arc is represented by three neurons (afferent, intercalary and efferent) and is called three-neuron or disynaptic. However, most reflex arcs include a large number of intercalary neurons, and are called polysynaptic (Fig. 10 A, B).
Reflex arcs can pass only through the spinal cord (withdrawal of the hand when touching a hot object), or only the brain (closing of the eyelids with a jet of air directed to the face), or both through the spinal cord and through the brain.
Rice. 10A. 1 - intercalary neuron; 2 - dendrite; 3 - neuron body; 4 - axon; 5 - synapse between sensitive and intercalary neurons; 6 - axon of a sensitive neuron; 7 - body of a sensitive neuron; 8 - axon of a sensitive neuron; 9 - axon of a motor neuron; 10 - body of a motor neuron; 11 - synapse between intercalary and motor neurons; 12 - receptor in the skin; 13 - muscle; 14 - sympathetic gaglia; 15 - gut.
Rice. 10B. 1 - monosynaptic reflex arc, 2 - polysynaptic reflex arc, 3K - posterior spinal root, PC - anterior spinal root.
Rice. 10. Scheme of the structure of the reflex arc
Reflex arcs are closed in reflex rings with the help of feedback. The concept of feedback and its functional role were indicated by Bell in 1826. Bell wrote that two-way connections are established between the muscle and the central nervous system. With the help of feedback, signals about the functional state of the effector are sent to the central nervous system.
The morphological basis of the feedback is the receptors located in the effector and the afferent neurons associated with them. Thanks to feedback afferent connections, fine regulation of the effector and an adequate response of the body to changes in the environment is carried out.
Shells of the brain
The central nervous system (spinal cord and brain) has three connective tissue membranes: hard, arachnoid and soft. The outermost of them is the dura mater (it grows together with the periosteum lining the surface of the skull). The arachnoid lies under the hard shell. It is tightly pressed against the solid and there is no free space between them.
Directly adjacent to the surface of the brain is the pia mater, in which there are many blood vessels that feed the brain. Between the arachnoid and soft shells there is a space filled with liquid - liquor. The composition of the cerebrospinal fluid is close to blood plasma and intercellular fluid and plays a shockproof role. In addition, the cerebrospinal fluid contains lymphocytes that provide protection from foreign substances. He is also involved in the metabolism between the cells of the spinal cord, brain and blood (Fig. 11 A).
1 - dentate ligament, the process of which passes through the arachnoid membrane located on the side, 1a - dentate ligament attached to the dura mater of the spinal cord, 2 - arachnoid membrane, 3 - posterior root, passing in the canal formed by the soft and arachnoid membranes, Za - posterior root passing through a hole in the dura mater of the spinal cord, 36 - dorsal branches of the spinal nerve passing through the arachnoid membrane, 4 - spinal nerve, 5 - spinal ganglion, 6 - dura mater of the spinal cord, 6a - dura mater turned to the side , 7 - pia mater of the spinal cord with the posterior spinal artery.
Rice. 11A. Meninges of the spinal cord
Cavities of the brain
Inside the spinal cord is the spinal canal, which, passing into the brain, expands in the medulla oblongata and forms the fourth ventricle. At the level of the midbrain, the ventricle passes into a narrow canal - the aqueduct of Sylvius. In the diencephalon, the aqueduct of Sylvius expands, forming a cavity of the third ventricle, which smoothly passes at the level of the cerebral hemispheres into the lateral ventricles (I and II). All of these cavities are also filled with CSF (Fig. 11 B)
Fig 11B. Scheme of the ventricles of the brain and their relationship to the surface structures of the cerebral hemispheres.
a - cerebellum, b - occipital pole, c - parietal pole, d - frontal pole, e - temporal pole, e - medulla oblongata.
1 - lateral opening of the fourth ventricle (Lushka's opening), 2 - inferior horn of the lateral ventricle, 3 - aqueduct, 4 - recessusinfundibularis, 5 - recrssusopticus, 6 - interventricular opening, 7 - anterior horn of the lateral ventricle, 8 - central part of the lateral ventricle, 9 - fusion of visual tubercles (massainter-melia), 10 - third ventricle, 11 -recessus pinealis, 12 - entrance to the lateral ventricle, 13 - posterior pro lateral ventricle, 14 - fourth ventricle.
Rice. 11. Shells (A) and cavities of the brain (B)
SECTION II. STRUCTURE OF THE CENTRAL NERVOUS SYSTEM
Spinal cord
The external structure of the spinal cord
The spinal cord is a flattened cord located in the spinal canal. Depending on the parameters of the human body, its length is 41–45 cm, the average diameter is 0.48–0.84 cm, and the weight is about 28–32 g. left half.
In front, the spinal cord passes into the brain, and behind it ends with a cerebral cone at the level of the 2nd vertebra of the lumbar spine. From the brain cone departs the connective tissue terminal thread (continuation of the terminal shells), which attaches the spinal cord to the coccyx. The terminal thread is surrounded by nerve fibers (cauda equina) (Fig. 12).
Two thickenings stand out on the spinal cord - cervical and lumbar, from which nerves depart, innervating, respectively, the skeletal muscles of the arms and legs.
In the spinal cord, cervical, thoracic, lumbar and sacral sections are distinguished, each of which is divided into segments: cervical - 8 segments, thoracic - 12, lumbar - 5, sacral 5-6 and 1 - coccygeal. Thus, the total number of segments is 31 (Fig. 13). Each segment of the spinal cord has paired spinal roots - anterior and posterior. Information from the receptors of the skin, muscles, tendons, ligaments, joints comes to the spinal cord through the posterior roots, therefore the posterior roots are called sensory (sensitive). Transection of the posterior roots turns off tactile sensitivity, but does not lead to loss of movement.
a - front view (its ventral surface);
b - rear view (its dorsal surface).
The hard and arachnoid membranes are cut. The vascular membrane has been removed. Roman numerals indicate the order of the cervical (c), thoracic (th), lumbar (t)
and sacral(s) spinal nerves.
1 - cervical thickening
2 - spinal ganglion
3 - hard shell
4 - lumbar thickening
5 - cerebral cone
6 - terminal thread
Rice. 13. Spinal cord and spinal nerves (31 pairs).
Through the anterior roots of the spinal cord, nerve impulses enter the skeletal muscles of the body (with the exception of the muscles of the head), causing them to contract, therefore the anterior roots are called motor or motor. After transection of the anterior roots on one side, there is a complete shutdown of motor reactions, while sensitivity to touch or pressure is preserved.
The anterior and posterior roots of each side of the spinal cord unite to form the spinal nerves. The spinal nerves are called segmental, their number corresponds to the number of segments and is 31 pairs (Fig. 14)
The distribution of zones of the spinal nerves by segments was determined by determining the size and boundaries of the skin areas (dermatomes) innervated by each nerve. Dermatomes are located on the surface of the body according to the segmental principle. Cervical dermatomes include the back of the head, neck, shoulders, and anterior forearms. Thoracic sensory neurons innervate the remaining surface of the forearm, chest, and most of the abdomen. Sensory fibers from the lumbar, sacral, and coccygeal segments fit into the rest of the abdomen and legs.
Rice. 14. Scheme of dermatomes. Innervation of the body surface by 31 pairs of spinal nerves (C - cervical, T - thoracic, L - lumbar, S - sacral).
Internal structure of the spinal cord
The spinal cord is built according to the nuclear type. Around the spinal canal is gray matter, on the periphery - white. Gray matter is formed by soma of neurons and branching dendrites that do not have myelin sheaths. White matter is a collection of nerve fibers covered with myelin sheaths.
In the gray matter, the anterior and posterior horns are distinguished, between which lies the interstitial zone. There are lateral horns in the thoracic and lumbar regions of the spinal cord.
The gray matter of the spinal cord is formed by two groups of neurons: efferent and intercalary. The bulk of the gray matter is made up of intercalary neurons (up to 97%) and only 3% are efferent neurons or motor neurons. Motor neurons are located in the anterior horns of the spinal cord. Among them, a- and g-motor neurons are distinguished: a-motor neurons innervate skeletal muscle fibers and are large cells with relatively long dendrites; g-motor neurons are represented by small cells and innervate muscle receptors, increasing their excitability.
Intercalary neurons are involved in information processing, ensuring the coordinated work of sensory and motor neurons, and also connect the right and left halves of the spinal cord and its various segments (Fig. 15 A, B, C)
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Rice. 15A. 1 - white matter of the brain; 2 - spinal canal; 3 - posterior longitudinal furrow; 4 - posterior root of the spinal nerve; 5 - spinal node; 6 - spinal nerve; 7 - gray matter of the brain; 8 - anterior root of the spinal nerve; 9 - anterior longitudinal furrow
Rice. 15B. Gray matter nuclei in the thoracic region
1,2,3 - sensitive nuclei of the posterior horn; 4, 5 - intercalary nuclei of the lateral horn; 6,7, 8,9,10 - motor nuclei of the anterior horn; I, II, III - anterior, lateral and posterior cords of the white matter.
The contacts between sensory, intercalary and motor neurons in the gray matter of the spinal cord are shown.
Rice. 15. Cross section of the spinal cord
Pathways of the spinal cord
The white matter of the spinal cord surrounds the gray matter and forms the columns of the spinal cord. Distinguish front, rear and side pillars. Pillars are tracts of the spinal cord formed by long axons of neurons that go up towards the brain (ascending paths) or down from the brain to the lower segments of the spinal cord (descending paths).
The ascending pathways of the spinal cord carry information from receptors in the muscles, tendons, ligaments, joints, and skin to the brain. Ascending paths are also conductors of temperature and pain sensitivity. All ascending pathways cross at the level of the spinal (or brain) cord. Thus, the left half of the brain (the cerebral cortex and cerebellum) receive information from the receptors of the right half of the body and vice versa.
Main ascending paths: from mechanoreceptors of the skin and receptors of the musculoskeletal system - these are muscles, tendons, ligaments, joints - the bundles of Gaulle and Burdach, or, respectively, they are the same - tender and wedge-shaped bundles are represented by the posterior columns of the spinal cord.
From the same receptors, information enters the cerebellum along two pathways represented by the lateral columns, which are called the anterior and posterior spinal tracts. In addition, two more paths pass in the lateral columns - these are the lateral and anterior spinal thalamic paths, which transmit information from temperature and pain sensitivity receptors.
The posterior columns provide faster information about the localization of irritations than the lateral and anterior spinal thalamic pathways (Fig. 16 A).
1 - Gaulle's bundle, 2 - Burdach's bundle, 3 - dorsal spinal cerebellar tract, 4 - ventral spinal cerebellar tract. Neurons of group I-IV.
Rice. 16A. Ascending tracts of the spinal cord
descending paths, passing as part of the anterior and lateral columns of the spinal cord, are motor, as they affect the functional state of the skeletal muscles of the body. The pyramidal path begins mainly in the motor cortex of the hemispheres and passes to the medulla oblongata, where most of the fibers cross and pass to the opposite side. After that, the pyramidal path is divided into lateral and anterior bundles: respectively, the anterior and lateral pyramidal paths. Most of the pyramidal tract fibers terminate on interneurons, and about 20% form synapses on motor neurons. The pyramidal influence is exciting. Reticulo-spinal way, rubrospinal way and vestibulospinal the path (extrapyramidal system) begins, respectively, from the nuclei of the reticular formation, the brain stem, the red nuclei of the midbrain and the vestibular nuclei of the medulla oblongata. These pathways run in the lateral columns of the spinal cord, are involved in the coordination of movements and the provision of muscle tone. Extrapyramidal paths, as well as pyramidal ones, are crossed (Fig. 16 B).
The main descending spinal tracts of the pyramidal (lateral and anterior corticospinal tracts) and extra pyramidal (rubrospinal, reticulospinal and vestibulospinal tracts) systems.
Rice. 16 B. Scheme of pathways
Thus, the spinal cord performs two important functions: reflex and conduction. The reflex function is carried out due to the motor centers of the spinal cord: the motor neurons of the anterior horns ensure the work of the skeletal muscles of the body. At the same time, maintaining muscle tone, coordinating the work of the flexor-extensor muscles underlying movements and maintaining the constancy of the posture of the body and its parts is maintained (Fig. 17 A, B, C). Motoneurons located in the lateral horns of the thoracic segments of the spinal cord provide respiratory movements (inhale-exhale, regulating the work of the intercostal muscles). Motoneurons of the lateral horns of the lumbar and sacral segments represent the motor centers of smooth muscles that make up the internal organs. These are the centers of urination, defecation, and the work of the genital organs.
Rice. 17A. The arc of the tendon reflex.
Rice. 17B. Arcs of the flexion and cross extensor reflex.
Rice. 17V. Elementary scheme of unconditioned reflex.
Nerve impulses that occur when the receptor (p) is stimulated along afferent fibers (afferent nerve, only one such fiber is shown) go to the spinal cord (1), where they are transmitted through the intercalary neuron to efferent fibers (eff. nerve), through which they reach effector. Dashed lines - the spread of excitation from the lower parts of the central nervous system to its higher parts (2, 3,4) up to the cerebral cortex (5) inclusive. The resulting change in the state of the higher parts of the brain, in turn, affects (see arrows) the efferent neuron, affecting the final result of the reflex response.
Rice. 17. Reflex function of the spinal cord
The conduction function is performed by the spinal tracts (Fig. 18 A, B, C, D, E).
Rice. 18A. Back poles. This circuit, formed by three neurons, transmits information from pressure and touch receptors to the somatosensory cortex.
Rice. 18B. Lateral spinal thalamic tract. Along this path, information from temperature and pain receptors enters vast areas of the thoracic medulla.
Rice. 18V. Anterior dorsal thalamic tract. Along this path, information from pressure and touch receptors, as well as from pain and temperature receptors, enters the somatosensory cortex.
Rice. 18G. extrapyramidal system. Rubrospinal and reticulospinal pathways, which are part of the multineuronal extrapyramidal pathway that runs from the cerebral cortex to the spinal cord.
Rice. 18D. Pyramidal, or corticospinal, path
Rice. 18. Conduction function of the spinal cord
SECTION III. BRAIN.
General scheme of the structure of the brain (Fig. 19)
Brain
Figure 19A. Brain
1. Frontal cortex (cognitive area)
2. Motor cortex
3. Visual cortex
4. Cerebellum 5. Auditory cortex
Fig 19B. Side view
Figure 19B. The main formations of the medal surface of the brain on the mid-sagittal section.
Fig 19D. Inferior surface of the brain
Rice. 19. The structure of the brain
Hind brain
The hindbrain, including the medulla oblongata and the pons Varolii, is a phylogenetically ancient region of the central nervous system, retaining the features of a segmental structure. In the hindbrain, nuclei and ascending and descending pathways are localized. Afferent fibers from the vestibular and auditory receptors, from the receptors of the skin and muscles of the head, from the receptors of the internal organs, as well as from the higher structures of the brain, enter the hindbrain along the conducting paths. The nuclei of the V-XII pairs of cranial nerves are located in the hindbrain, some of which innervates the facial and oculomotor muscles.
Medulla
The medulla oblongata is located between the spinal cord, the pons and the cerebellum (Fig. 20). On the ventral surface of the medulla oblongata, the anterior median sulcus runs along the midline, on its sides there are two strands - pyramids, olives lie on the side of the pyramids (Fig. 20 A-B).
Rice. 20A. 1 - cerebellum 2 - cerebellar peduncles 3 - pons 4 - medulla oblongata
Rice. 20V. 1 - bridge 2 - pyramid 3 - olive 4 - anterior median fissure 5 - anterior lateral groove 6 - cross of the anterior funiculus 7 - anterior funiculus 8 - lateral funiculus
Rice. 20. Medulla oblongata
On the back side of the medulla oblongata stretches the posterior medial sulcus. On its sides lie the posterior cords, which go to the cerebellum as part of the hind legs.
Gray matter of the medulla oblongata
The nuclei of the four pairs of cranial nerves are located in the medulla oblongata. These include the nuclei of the glossopharyngeal, vagus, accessory, and hypoglossal nerves. In addition, the tender, sphenoid nuclei and cochlear nuclei of the auditory system, the nuclei of the lower olives and the nuclei of the reticular formation (giant cell, small cell and lateral), as well as the respiratory nuclei are isolated.
The nuclei of the hyoid (XII pair) and accessory (XI pair) nerves are motor, they innervate the muscles of the tongue and the muscles that move the head. The nuclei of the vagus (X pair) and glossopharyngeal (IX pair) nerves are mixed, they innervate the muscles of the pharynx, larynx, thyroid gland, and regulate swallowing and chewing. These nerves consist of afferent fibers coming from the receptors of the tongue, larynx, trachea and from the receptors of the internal organs of the chest and abdominal cavity. Efferent nerve fibers innervate the intestines, heart and blood vessels.
The nuclei of the reticular formation not only activate the cerebral cortex, supporting consciousness, but also form a respiratory center that provides respiratory movements.
Thus, part of the nuclei of the medulla oblongata regulates vital functions (these are the nuclei of the reticular formation and the nuclei of the cranial nerves). Another part of the nuclei is part of the ascending and descending tracts (tender and sphenoid nuclei, cochlear nuclei of the auditory system) (Fig. 21).
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2 - wedge-shaped nucleus;
3 - the end of the fibers of the posterior cords of the spinal cord;
4 - internal arcuate fibers - the second neuron of the cortical pathway;
5 - the intersection of the loops is located in the inter-shedding loop layer;
6 - medial loop - continuation of the internal arcuate ox
7 - a seam formed by a cross of loops;
8 - the core of the olive - the intermediate core of equilibrium;
9 - pyramidal paths;
10 - central channel.
Rice. 21. Internal structure of the medulla oblongata
White matter of the medulla oblongata
The white matter of the medulla oblongata is formed by long and short nerve fibers.
Long nerve fibers are part of the descending and ascending pathways. Short nerve fibers ensure the coordinated work of the right and left halves of the medulla oblongata.
pyramids medulla oblongata - part descending pyramidal tract, going to the spinal cord and ending in intercalary neurons and motor neurons. In addition, the rubro-spinal path passes through the medulla oblongata. The descending vestibulospinal and reticulospinal tracts originate in the medulla oblongata, respectively, from the vestibular and reticular nuclei.
The ascending spinal tracts pass through olives medulla oblongata and through the legs of the brain and transmit information from the receptors of the musculoskeletal system to the cerebellum.
gentle and wedge-shaped nuclei medulla oblongata are part of the spinal cord pathways of the same name, going through the visual tubercles of the diencephalon to the somatosensory cortex.
Through cochlear auditory nuclei and through vestibular nuclei ascending sensory pathways from the auditory and vestibular receptors. In the projection zone of the temporal cortex.
Thus, the medulla oblongata regulates the activity of many vital functions of the body. Therefore, the slightest damage to the medulla oblongata (trauma, edema, hemorrhage, tumors), as a rule, leads to death.
Pons
The bridge is a thick roller that borders the medulla oblongata and cerebellar peduncles. The ascending and descending paths of the medulla oblongata pass through the bridge without interruption. The vestibulocochlear nerve (VIII pair) exits at the junction of the pons and the medulla oblongata. The vestibulocochlear nerve is sensitive and transmits information from auditory and vestibular receptors in the inner ear. In addition, mixed nerves, nuclei of the trigeminal nerve (V pair), abducens nerve (VI pair), and facial nerve (VII pair) are located in the pons Varolii. These nerves innervate the muscles of the face, scalp, tongue, and lateral rectus muscles of the eye.
On the transverse section, the bridge consists of the ventral and dorsal parts - between them the border is a trapezoid body, the fibers of which are attributed to the auditory pathway. In the region of the trapezius body there is a medial parabranchial nucleus, which is associated with the dentate nucleus of the cerebellum. The pons proper nucleus connects the cerebellum with the cerebral cortex. In the dorsal part of the bridge lie the nuclei of the reticular formation and continue the ascending and descending paths of the medulla oblongata.
The bridge performs complex and diverse functions aimed at maintaining the posture and maintaining the balance of the body in space when changing the speed of movement.
Vestibular reflexes are very important, the reflex arcs of which pass through the bridge. They provide the tone of the neck muscles, excitation of the vegetative centers, respiration, heart rate, and activity of the gastrointestinal tract.
The nuclei of the trigeminal, glossopharyngeal, vagus, and pons are involved in grasping, chewing, and swallowing food.
Neurons of the pontine reticular formation play a special role in activating the cerebral cortex and limiting the sensory influx of nerve impulses during sleep (Fig. 22, 23)
Rice. 22. Medulla oblongata and pons.
A. Top view (from the dorsal side).
B. Side view.
B. View from below (from the ventral side).
1 - tongue, 2 - anterior cerebral sail, 3 - median eminence, 4 - superior fossa, 5 - superior cerebellar peduncle, 6 - middle cerebellar peduncle, 7 - facial tubercle, 8 - inferior cerebellar peduncle, 9 - auditory tubercle, 10 - brain stripes, 11 - ribbon of the fourth ventricle, 12 - triangle of the hypoglossal nerve, 13 - triangle of the vagus nerve, 14 - areapos-terma, 15 - obex, 16 - tubercle of the sphenoid nucleus, 17 - tubercle of the tender nucleus, 18 - lateral funiculus, 19 - posterior lateral sulcus, 19 a - anterior lateral sulcus, 20 - sphenoid funiculus, 21 - posterior intermediate sulcus, 22 - tender cord, 23 - posterior median sulcus, 23 a - bridge - base), 23 b - pyramid of the medulla oblongata, 23 c - olive, 23 g - cross of the pyramids, 24 - leg of the brain, 25 - lower tubercle, 25 a - handle of the lower tubercle, 256 - upper tubercle
1 - trapezoid body 2 - core of the superior olive 3 - dorsal contains nuclei of VIII, VII, VI, V pairs of cranial nerves 4 - medal part of the bridge 5 - ventral part of the bridge contains its own nuclei and bridge 7 - transverse nuclei of the bridge 8 - pyramidal pathways 9 - middle cerebellar peduncle.
Rice. 23. Scheme of the internal structure of the bridge on the frontal section
Cerebellum
The cerebellum is a region of the brain located behind the cerebral hemispheres above the medulla oblongata and the pons.
Anatomically, in the cerebellum, the middle part is distinguished - the worm, and two hemispheres. With the help of three pairs of legs (lower, middle and upper), the cerebellum is connected to the brain stem. The lower legs connect the cerebellum with the medulla oblongata and spinal cord, the middle ones with the bridge, and the upper ones with the middle and diencephalon (Fig. 24).
1 - vermis 2 - central lobule 3 - uvula of the vermis 4 - anterior cerebellar velum 5 - superior hemisphere 6 - anterior cerebellar peduncle 8 - pedicle of the tuft 9 - tuft 10 - superior lunate lobule 11 - inferior lunate lobule 12 - inferior hemisphere 13 - digastric lobule 14 - cerebellar lobule 15 - cerebellar tonsil 16 - pyramid of the vermis 17 - wing of the central lobule 18 - nodule 19 - apex 20 - groove 21 - worm socket 22 - worm tubercle 23 - quadrangular lobule.
Rice. 24. Internal structure of the cerebellum
The cerebellum is built according to the nuclear type - the surface of the hemispheres is represented by gray matter, which makes up the new cortex. The bark forms convolutions, which are separated from each other by furrows. Under the cerebellar cortex there is a white matter, in the thickness of which the paired nuclei of the cerebellum are isolated (Fig. 25). These include the kernels of the tent, the spherical nucleus, the cork nucleus, the dentate nucleus. The nuclei of the tent are associated with the vestibular apparatus, the spherical and cork nuclei with the movement of the body, the dentate nucleus with the movement of the limbs.
1- anterior legs of the cerebellum; 2 - the core of the tent; 3 - dentate nucleus; 4 - cork-like nucleus; 5 - white substance; 6 - hemispheres of the cerebellum; 7 - worm; 8 globular nucleus
Rice. 25. Cerebellar nuclei
The cerebellar cortex is of the same type and consists of three layers: molecular, ganglionic and granular, in which there are 5 types of cells: Purkinje cells, basket cells, stellate cells, granular cells and Golgi cells (Fig. 26). In the surface, molecular layer, there are dendritic branches of Purkinje cells, which are one of the most complex neurons in the brain. The dendritic processes are abundantly covered with spines, indicating a large number of synapses. In addition to Purkinje cells, this layer contains many axons of parallel nerve fibers (T-shaped branching axons of granule cells). In the lower part of the molecular layer are the bodies of basket cells, the axons of which form synaptic contacts in the region of the axon mounds of Purkinje cells. There are also stellate cells in the molecular layer.
A. Purkinje cell. B. Grain cells.
B. Golgi cell.
Rice. 26. Types of cerebellar neurons.
Beneath the molecular layer is the ganglionic layer, which houses the Purkinje cell bodies.
The third layer - granular - is represented by the bodies of intercalary neurons (grain cells or granule cells). In the granular layer there are also Golgi cells, the axons of which rise into the molecular layer.
Only two types of afferent fibers enter the cerebellar cortex: climbing and mossy, through which nerve impulses arrive in the cerebellum. Each climbing fiber has contact with one Purkinje cell. The ramifications of the mossy fiber form contacts mainly with granular neurons, but do not contact with Purkinje cells. The synapses of the mossy fiber are excitatory (Fig. 27).
The cortex and nuclei of the cerebellum receive excitatory impulses through both climbing and bryophyte fibers. From the cerebellum, the signals come only from Purkinje cells (P), which inhibit the activity of neurons in the nuclei of the 1st cerebellum (I). The intrinsic neurons of the cerebellar cortex include excitatory granule cells (3) and inhibitory basket neurons (K), Golgi neurons (G) and stellate neurons (Sv). Arrows indicate the direction of movement of nerve impulses. There are both exciting (+) and; inhibitory (-) synapses.
Rice. 27. Neural circuit of the cerebellum.
Thus, two types of afferent fibers enter the cerebellar cortex: climbing and mossy. Information is transmitted through these fibers from tactile receptors and receptors of the musculoskeletal system, as well as from all brain structures that regulate the motor function of the body.
The efferent influence of the cerebellum is carried out through the axons of Purkinje cells, which are inhibitory. The axons of Purkinje cells exert their influence either directly on the motor neurons of the spinal cord, or indirectly through the neurons of the cerebellar nuclei or other motor centers.
In humans, due to upright posture and labor activity, the cerebellum and its hemispheres reach the greatest development and size.
With damage to the cerebellum, imbalance and muscle tone are observed. The nature of the damage depends on the location of the damage. So, when the nuclei of the tent are damaged, the balance of the body is disturbed. This is manifested in a staggering gait. If the worm, cork and spherical nuclei are damaged, the work of the muscles of the neck and torso is disrupted. The patient has difficulty eating. With damage to the hemispheres and the dentate nucleus - the work of the muscles of the limbs (tremor), its professional activity is hampered.
In addition, in all patients with damage to the cerebellum due to impaired coordination of movements and tremor (trembling), fatigue quickly occurs.
midbrain
The midbrain, like the medulla oblongata and the pons Varolii, belongs to the stem structures (Fig. 28).
1 - komisura leashes
2 - leash
3 - pineal gland
4 - superior colliculus of the midbrain
5 - medial geniculate body
6 - lateral geniculate body
7 - lower colliculus of the midbrain
8 - upper legs of the cerebellum
9 - middle legs of the cerebellum
10 - lower legs of the cerebellum
11- medulla oblongata
Rice. 28. Hind brain
The midbrain consists of two parts: the roof of the brain and the legs of the brain. The roof of the midbrain is represented by the quadrigemina, in which the upper and lower tubercles are distinguished. In the thickness of the legs of the brain, paired clusters of nuclei are distinguished, called the black substance and the red nucleus. Through the midbrain, ascending paths pass to the diencephalon and cerebellum and descending paths - from the cerebral cortex, subcortical nuclei and diencephalon to the nuclei of the medulla oblongata and spinal cord.
In the lower colliculus of the quadrigemina are neurons that receive afferent signals from auditory receptors. Therefore, the lower tubercles of the quadrigemina are called the primary auditory center. The reflex arc of the orienting auditory reflex passes through the primary auditory center, which manifests itself in turning the head towards the acoustic signal.
The superior tubercles of the quadrigemina are the primary visual center. The neurons of the primary visual center receive afferent impulses from photoreceptors. The superior tubercles of the quadrigemina provide an orienting visual reflex - turning the head in the direction of the visual stimulus.
In the implementation of the orienting reflexes, the nuclei of the lateral and oculomotor nerves take part, which innervate the muscles of the eyeball, ensuring its movement.
The red nucleus contains neurons of different sizes. From the large neurons of the red nucleus, the descending rubro-spinal tract begins, which has an effect on motor neurons and finely regulates muscle tone.
The neurons of the substantia nigra contain the pigment melanin and give this nucleus its dark color. The substantia nigra, in turn, sends signals to the neurons of the reticular nuclei of the brain stem and subcortical nuclei.
The substantia nigra is involved in complex coordination of movements. It contains dopaminergic neurons, i.e. releasing dopamine as a mediator. One part of these neurons regulates emotional behavior, while the other part plays an important role in the control of complex motor acts. Damage to the substantia nigra, leading to degeneration of dopaminergic fibers, causes the inability to start performing voluntary movements of the head and hands when the patient is sitting quietly (Parkinson's disease) (Fig. 29 A, B).
Rice. 29A. 1 - hillock 2 - cerebral aqueduct 3 - central gray matter 4 - substantia nigra 5 - medial sulcus of the cerebral peduncle
Rice. 29B. Scheme of the internal structure of the midbrain at the level of the inferior colliculi (frontal section)
1 - nucleus of the inferior colliculus, 2 - motor pathway of the extrapyramidal system, 3 - dorsal decussation of the tegmentum, 4 - red nucleus, 5 - red nuclear - spinal tract, 6 - ventral decussation of the tegmentum, 7 - medial loop, 8 - lateral loop, 9 - reticular formation, 10 - medial longitudinal bundle, 11 - nucleus of the mesencephalic tract of the trigeminal nerve, 12 - nucleus of the lateral nerve, I-V - descending motor pathways of the brain stem
Rice. 29. Scheme of the internal structure of the midbrain
diencephalon
The diencephalon forms the walls of the third ventricle. Its main structures are the visual tubercles (thalamus) and the hypothalamic region (hypothalamus), as well as the suprathalamic region (epithalamus) (Fig. 30 A, B).
Rice. 30 A. 1 - thalamus (visual tubercle) - the subcortical center of all types of sensitivity, the "sensory" of the brain; 2 - epithalamus (supratuberous region); 3 - metathalamus (foreign region).
Rice. 30 B. Diagrams of the visual brain ( thalamencephalon ): a - top view b - rear and bottom view.
Thalamus (thalamus) 1 - anterior burf of the thalamus, 2 - pillow 3 - intertubercular fusion 4 - brain strip of the thalamus
Epithalamus (supratuberous region) 5 - triangle of the leash, 6 - leash, 7 - commissure of the leash, 8 - pineal body (pineal gland)
Metathalamus (foreign region) 9 - lateral geniculate body, 10 - medial geniculate body, 11 - III ventricle, 12 - roof of the midbrain
Rice. 30. Visual Brain
In the depths of the brain tissue of the diencephalon are the nuclei of the external and internal geniculate bodies. The outer border is formed by white matter separating the diencephalon from the final.
Thalamus (optical tubercles)
The neurons of the thalamus form 40 nuclei. Topographically, the nuclei of the thalamus are divided into anterior, median and posterior. Functionally, these nuclei can be divided into two groups: specific and nonspecific.
Specific nuclei are part of specific pathways. These are ascending pathways that transmit information from the receptors of the sense organs to the projection zones of the cerebral cortex.
The most important of the specific nuclei are the lateral geniculate body, which is involved in the transmission of signals from photoreceptors, and the medial geniculate body, which transmits signals from auditory receptors.
Nonspecific thalamic ridges are referred to as the reticular formation. They play the role of integrative centers and have a predominantly activating ascending effect on the cortex of the cerebral hemispheres (Fig. 31 A, B)
1 - front group (olfactory); 2 - rear group (visual); 3 - lateral group (general sensitivity); 4 - medial group (extrapyramidal system; 5 - central group (reticular formation).
Rice. 31B. Frontal section of the brain at the level of the middle of the thalamus. 1a - anterior nucleus of the thalamus. 16 - medial nucleus of the thalamus, 1c - lateral nucleus of the thalamus, 2 - lateral ventricle, 3 - fornix, 4 - caudate nucleus, 5 - internal capsule, 6 - external capsule, 7 - external capsule (capsulaextrema), 8 - ventral nucleus visual mound, 9 - subthalamic nucleus, 10 - third ventricle, 11 - brain stem. 12 - bridge, 13 - interpeduncular fossa, 14 - hippocampal stalk, 15 - lower horn of the lateral ventricle. 16 - black substance, 17 - island. 18 - pale ball, 19 - shell, 20 - Trout H fields; and b. 21 - interthalamic fusion, 22 - corpus callosum, 23 - tail of the caudate nucleus.
Fig 31. Scheme of groups of nuclei of the thalamus
Activation of neurons of nonspecific nuclei of the thalamus is especially effectively caused by pain signals (thalamus is the highest center of pain sensitivity).
Damage to the nonspecific nuclei of the thalamus also leads to a violation of consciousness: the loss of the body's active connection with the environment.
hypothalamus (hypothalamus)
The hypothalamus is formed by a group of nuclei located at the base of the brain. The nuclei of the hypothalamus are the subcortical centers of the autonomic nervous system of all vital body functions.
Topographically, the hypothalamus is divided into the preoptic region, the regions of the anterior, middle and posterior hypothalamus. All nuclei of the hypothalamus are paired (Figure 32 A-D).
1 - plumbing 2 - red core 3 - tire 4 - black substance 5 - brain stem 6 - mastoid bodies 7 - anterior perforated substance 8 - olfactory triangle 9 - funnel 10 - optic chiasm 11. optic nerve 12 - gray tubercle 13 - posterior perforated substance 14 - lateral geniculate body 15 - medial geniculate body 16 - pillow 17 - optic tract
Rice. 32A. Metathalamus and hypothalamus
a - bottom view; b - median sagittal section.
Visual part (parsoptica): 1 - end plate; 2 - optic chiasm; 3 - visual tract; 4 - gray tubercle; 5 - funnel; 6 - pituitary gland;
Olfactory part: 7 - mammillary bodies - subcortical olfactory centers; 8 - the hypothalamic region in the narrow sense of the word is a continuation of the legs of the brain, contains a black substance, a red nucleus and a Lewis body, which is a link in the extrapyramidal system and a vegetative center; 9 - hypotuberous Monroe's furrow; 10 - Turkish saddle, in the fossa of which is the pituitary gland.
Rice. 32B. Hypodermic area (hypothalamus)
Rice. 32V. Major nuclei of the hypothalamus
1 - nucleus supraopticus; 2 - nucleuspreopticus; 3 - nuclius paraventricularis; 4 - nucleusinfundibularus; 5 - nucleuscorporismamillaris; 6 - optic chiasm; 7 - pituitary gland; 8 - gray tubercle; 9 - mastoid body; 10 bridge.
Rice. 32G. Diagram of the neurosecretory nuclei of the hypothalamic region (Hypothalamus)
The preoptic region includes the periventricular, medial, and lateral preoptic nuclei.
The anterior hypothalamus includes the supraoptic, suprachiasmatic, and paraventricular nuclei.
The middle hypothalamus makes up the ventromedial and dorsomedial nuclei.
In the posterior hypothalamus, the posterior hypothalamic, perifornical, and mamillary nuclei are distinguished.
The connections of the hypothalamus are extensive and complex. Afferent signals to the hypothalamus come from the cerebral cortex, subcortical nuclei and from the thalamus. The main efferent pathways reach the midbrain, thalamus and subcortical nuclei.
The hypothalamus is the highest center of regulation of the cardiovascular system, water-salt, protein, fat, carbohydrate metabolism. In this area of the brain are centers associated with the regulation of eating behavior. An important role of the hypothalamus is regulation. Electrical stimulation of the posterior nuclei of the hypothalamus leads to hyperthermia, as a result of an increase in metabolism.
The hypothalamus is also involved in maintaining the sleep-wake biorhythm.
The nuclei of the anterior hypothalamus are connected with the pituitary gland and carry out the transport of biologically active substances that are produced by the neurons of these nuclei. The neurons of the preoptic nucleus produce releasing factors (statins and liberins) that control the synthesis and release of pituitary hormones.
The neurons of the preoptic, supraoptic, paraventricular nuclei produce true hormones - vasopressin and oxytocin, which descend along the axons of the neurons to the neurohypophysis, where they are stored until they are released into the blood.
Neurons of the anterior pituitary gland produce 4 types of hormones: 1) somatotropic hormone that regulates growth; 2) a gonadotropic hormone that promotes the growth of germ cells, the corpus luteum, enhances milk production; 3) thyroid-stimulating hormone - stimulates the function of the thyroid gland; 4) adrenocorticotropic hormone - enhances the synthesis of hormones of the adrenal cortex.
The intermediate lobe of the pituitary gland secretes the hormone intermedin, which affects skin pigmentation.
The posterior pituitary gland secretes two hormones - vasopressin, which affects the smooth muscles of the arterioles, and oxytocin - acts on the smooth muscles of the uterus and stimulates the release of milk.
The hypothalamus also plays an important role in emotional and sexual behavior.
The pineal gland is part of the epithalamus (pineal gland). Pineal hormone - melatonin - inhibits the formation of gonadotropic hormones in the pituitary gland, and this in turn delays sexual development.
forebrain
The forebrain consists of three anatomically separate parts - the cerebral cortex, white matter and subcortical nuclei.
In accordance with the phylogeny of the cerebral cortex, the ancient cortex (archicortex), the old cortex (paleocortex) and the new cortex (neocortex) are distinguished. The ancient cortex includes olfactory bulbs, which receive afferent fibers from the olfactory epithelium, olfactory tracts - located on the lower surface of the frontal lobe and olfactory tubercles - secondary olfactory centers.
The old cortex includes the cingulate cortex, the hippocampal cortex, and the amygdala.
All other areas of the cortex are new cortex. The ancient and old cortex is called the olfactory brain (Fig. 33).
The olfactory brain, in addition to the functions associated with smell, provides reactions of alertness and attention, takes part in the regulation of the autonomic functions of the body. This system also plays an important role in the implementation of instinctive forms of behavior (food, sexual, defensive) and the formation of emotions.
a - bottom view; b - on the sagittal section of the brain
Peripheral department: 1 - bulbusolfactorius (olfactory bulb; 2 - tractusolfactories (olfactory pathway); 3 - trigonumolfactorium (olfactory triangle); 4 - substantiaperforateanterior (anterior perforated substance).
The central section is the gyrus of the brain: 5 - vaulted gyrus; 6 - hippocampus is located in the cavity of the lower horn of the lateral ventricle; 7 - continuation of the gray vestment of the corpus callosum; 8 - vault; 9 - transparent septum conducting paths of the olfactory brain.
Figure 33. Olfactory brain
Irritation of the structures of the old cortex affects the cardiovascular system and respiration, causes hypersexuality, and changes emotional behavior.
With electrical stimulation of the tonsils, effects associated with the activity of the digestive tract are observed: licking, chewing, swallowing, changes in intestinal motility. Irritation of the tonsil also affects the activity of internal organs - the kidneys, bladder, uterus.
Thus, there is a connection between the structures of the old cortex and the autonomic nervous system, with processes aimed at maintaining the homeostasis of the internal environment of the body.
telencephalon
The structure of the telencephalon includes: the cerebral cortex, white matter and subcortical nuclei located in its thickness.
The surface of the cerebral hemispheres is folded. Furrows - depressions divide it into shares.
The central (Roland) sulcus separates the frontal lobe from the parietal lobe. The lateral (Sylviian) sulcus separates the temporal lobe from the parietal and frontal lobes. The occipital-parietal sulcus forms the border between the parietal, occipital and temporal lobes (Fig. 34 A, B, Fig. 35)
1 - superior frontal gyrus; 2 - middle frontal gyrus; 3 - precentral gyrus; 4 - postcentral gyrus; 5 - lower parietal gyrus; 6 - superior parietal gyrus; 7 - occipital gyrus; 8 - occipital groove; 9 - intraparietal groove; 10 - central furrow; 11 - precentral gyrus; 12 - lower frontal groove; 13 - upper frontal groove; 14 - vertical slot.
Rice. 34A. The brain from the dorsal surface
1 - olfactory groove; 2 - anterior perforated substance; 3 - hook; 4 - middle temporal sulcus; 5 - lower temporal sulcus; 6 - furrow of a seahorse; 7 - circumferential furrow; 8 - spur furrow; 9 - wedge; 10 - parahippocampal gyrus; 11 - occipital-temporal groove; 12 - lower parietal gyrus; 13 - olfactory triangle; 14 - direct gyrus; 15 - olfactory tract; 16 - olfactory bulb; 17 - vertical slot.
Rice. 34B. The brain from the ventral surface
1 - central furrow (Roland); 2 - lateral furrow (Sylvian furrow); 3 - precentral furrow; 4 - upper frontal groove; 5 - lower frontal furrow; 6 - ascending branch; 7 - front branch; 8 - transcentral furrow; 9 - intraparietal groove; 10- superior temporal sulcus; 11 - lower temporal sulcus; 12 - transverse occipital sulcus; 13 - occipital sulcus.
Rice. 35. Furrows of the upper lateral surface of the hemisphere (left side)
Thus, the furrows divide the hemispheres of the telencephalon into five lobes: the frontal, parietal, temporal, occipital and insular lobes, which are located under the temporal lobes (Fig. 36).
Rice. 36. Projection (marked with dots) and associative (light) areas of the cerebral cortex. The projection areas include the motor area (frontal lobe), the somatosensory area (parietal lobe), the visual area (occipital lobe), and the auditory area (temporal lobe).
Furrows are also located on the surface of each lobe.
There are three orders of furrows: primary, secondary and tertiary. The primary furrows are relatively stable and the deepest. These are the boundaries of large morphological parts of the brain. The secondary furrows depart from the primary, and the tertiary from the secondary.
Between the furrows there are folds - convolutions, the shape of which is determined by the configuration of the furrows.
In the frontal lobe, the superior, middle, and inferior frontal gyri are distinguished. The temporal lobe contains the superior, middle, and inferior temporal gyri. The anterior central gyrus (precentral) is located in front of the central sulcus. The posterior central gyrus (postcentral) lies behind the central sulcus.
In humans, there is a large variability of the furrows and convolutions of the telencephalon. Despite this individual variability in the external structure of the hemispheres, this does not affect the structure of personality and consciousness.
Cytoarchitectonics and myeloarchitectonics of the neocortex
In accordance with the division of the hemispheres into five lobes, five main areas are distinguished - frontal, parietal, temporal, occipital and insular, which have differences in structure and perform different functions. However, the general plan of the structure of the new crust is the same. The neocortex is a layered structure (Fig. 37). I - molecular layer, formed mainly by nerve fibers running parallel to the surface. A small number of granular cells are located among the parallel fibers. Under the molecular layer is layer II - the outer granular one. Layer III - external pyramidal, IV layer, internal granular, V layer - internal pyramidal and VI layer - multiform. The names of the layers are given by the name of the neurons. Accordingly, in layers II and IV, the soma of neurons have a rounded shape (grain cells) (outer and inner granular layers), and in layers III and IV, the somas have a pyramidal shape (in the outer pyramidal - small pyramids, and in the inner pyramid - large pyramids or Betz cells). Layer VI is characterized by the presence of neurons of various shapes (fusiform, triangular, etc.).
The main afferent inputs to the cerebral cortex are nerve fibers coming from the thalamus. Cortical neurons that perceive afferent impulses going through these fibers are called sensory, and the area where sensory neurons are located is called projection cortical zones.
The main efferent outputs from the cortex are the axons of the layer V pyramids. These are efferent, motor neurons involved in the regulation of motor functions. Most cortical neurons are intercalary, involved in information processing and providing intercortical connections.
Typical cortical neurons
Roman numerals denote cell layers. I - molecular structure; II - outer granular layer; III - outer pyramidal layer; IV - inner granular layer; V - inner amide layer; VI-multiform layer.
a - afferent fibers; b - cell types detected on preparations impregnated by the Goldbzhi method; c - cytoarchitectonics revealed by Nissl staining. 1 - horizontal cells, 2 - Kes's strip, 3 - pyramidal cells, 4 - stellate cells, 5 - external Bellarge's strip, 6 - internal Bellarge's strip, 7 - modified pyramidal cell.
Rice. 37. Cytoarchitectonics (A) and myeloarchitectonics (B) of the cerebral cortex.
While maintaining the general plan of the structure, it was found that different parts of the bark (within the same area) differ in the thickness of the layers. In some layers, several sublayers can be distinguished. In addition, there are differences in cellular composition (diversity of neurons, density and their location). Taking into account all these differences, Brodman identified 52 areas, which he called cytoarchitectonic fields and designated with Arabic numerals from 1 to 52 (Fig. 38 A, B).
A side view. B mid-sagittal; cut.
Rice. 38. The layout of the fields according to Boardman
Each cytoarchitectonic field differs not only in its cellular structure, but also in the location of nerve fibers, which can go both in vertical and horizontal directions. The accumulation of nerve fibers within the cytoarchitectonic field is called myeloarchitectonics.
At present, the "columnar principle" of the organization of the projection zones of the cortex is gaining more and more recognition.
According to this principle, each projection zone consists of a large number of vertically oriented columns, approximately 1 mm in diameter. Each column unites about 100 neurons, among which there are sensory, intercalary and efferent neurons interconnected by synaptic connections. A single “cortical column” is involved in the processing of information from a limited number of receptors, i.e. performs a specific function.
Hemispheric fiber system
Both hemispheres have three types of fibers. Through projection fibers, excitation enters the cortex from receptors along specific pathways. Associative fibers connect different areas of the same hemisphere. For example, the occipital region with the temporal region, the occipital region with the frontal region, the frontal region with the parietal region. Commissural fibers connect symmetrical regions of both hemispheres. Among the commissural fibers, there are: anterior, posterior cerebral commissures and the corpus callosum (Fig. 39 A.B).
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Rice. 39A. a - medial surface of the hemisphere;
b - upper lateral surface of the hemisphere;
A - frontal pole;
B - occipital pole;
C - corpus callosum;
1 - arcuate fibers of the cerebrum connect adjacent gyri;
2 - belt - a bundle of the olfactory brain lies under the vaulted gyrus, extends from the region of the olfactory triangle to the hook;
3 - the lower longitudinal bundle connects the occipital and temporal region;
4 - the upper longitudinal bundle connects the frontal, occipital, temporal lobes and the lower parietal lobule;
5 - a hook-shaped bundle is located at the anterior edge of the island and connects the frontal pole with the temporal.
Rice. 39B. The cerebral cortex in cross section. Both hemispheres are connected by bundles of white matter, forming the corpus callosum (commissural fibers).
Rice. 39. Scheme of associative fibers
Reticular formation
The reticular formation (the reticulum of the brain) was described by anatomists at the end of the last century.
The reticular formation begins in the spinal cord, where it is represented by the gelatinous substance of the base of the hindbrain. Its main part is located in the central brain stem and in the diencephalon. It consists of neurons of various shapes and sizes, which have extensive branching processes going in different directions. Among the processes, short and long nerve fibers are distinguished. Short processes provide local connections, long processes form ascending and descending paths of the reticular formation.
Accumulations of neurons form nuclei that are located at different levels of the brain (spinal, oblong, middle, intermediate). Most of the nuclei of the reticular formation do not have clear morphological boundaries and the neurons of these nuclei are combined only according to a functional feature (respiratory, cardiovascular center, etc.). However, at the level of the medulla oblongata, nuclei with clearly defined boundaries are distinguished - reticular giant cell, reticular small cell and lateral nuclei. The nuclei of the reticular formation of the bridge are essentially a continuation of the nuclei of the reticular formation of the medulla oblongata. The largest of them are the caudal, medial and oral nuclei. The latter passes into the cellular group of nuclei of the reticular formation of the midbrain and the reticular nucleus of the tegmentum. The cells of the reticular formation are the beginning of both ascending and descending pathways, giving numerous collaterals (endings) that form synapses on neurons of different nuclei of the central nervous system.
Fibers of reticular cells traveling to the spinal cord form the reticulospinal tract. The fibers of the ascending tracts, starting in the spinal cord, connect the reticular formation with the cerebellum, midbrain, diencephalon, and cerebral cortex.
Allocate specific and non-specific reticular formation. For example, some of the ascending pathways of the reticular formation receive collaterals from specific pathways (visual, auditory, etc.) through which afferent impulses are transmitted to the projection zones of the cortex.
Nonspecific ascending and descending pathways of the reticular formation affect the excitability of various parts of the brain, primarily the cerebral cortex and the spinal cord. According to their functional value, these influences can be both activating and inhibitory, therefore, they distinguish: 1) ascending activating influence, 2) ascending inhibitory influence, 3) descending activating influence, 4) descending inhibitory influence. Based on these factors, the reticular formation is considered as a non-specific regulatory system of the brain.
The most studied activating effect of the reticular formation on the cerebral cortex. Most of the ascending fibers of the reticular formation diffusely terminate in the cortex of the hemispheres and maintain its tone and provide attention. An example of inhibitory descending influences of the reticular formation is a decrease in the tone of human skeletal muscles during certain stages of sleep.
Neurons of the reticular formation are extremely sensitive to humoral substances. This is an indirect mechanism of the influence of various humoral factors and the endocrine system on the higher parts of the brain. Consequently, the tonic effects of the reticular formation depend on the state of the whole organism (Fig. 40).
Rice. 40. The activating reticular system (ARS) is a nervous network through which sensory excitation is transmitted from the reticular formation of the brain stem to the nonspecific nuclei of the thalamus. Fibers from these nuclei regulate the activity level of the cortex.
Subcortical nuclei
The subcortical nuclei are part of the telencephalon and are located inside the white matter of the cerebral hemispheres. These include the caudate body and the shell, united under the general name "striated body" (striatum) and the pale ball, consisting of the lenticular body, husk and tonsil. The subcortical nuclei and nuclei of the midbrain (red nucleus and black substance) make up the system of basal ganglia (nuclei) (Fig. 41). The basal ganglia receive impulses from the motor cortex and cerebellum. In turn, signals from the basal ganglia are sent to the motor cortex, cerebellum and reticular formation, i.e. there are two neural loops: one connects the basal ganglia with the motor cortex, the other with the cerebellum.
Rice. 41. Basal ganglia system
The subcortical nuclei are involved in the regulation of motor activity, regulating complex movements when walking, maintaining a posture, and eating. They organize slow movements (stepping over obstacles, threading a needle, etc.).
There is evidence that the striatum is involved in the processes of memorizing motor programs, since irritation of this structure leads to impaired learning and memory. The striatum has an inhibitory effect on various manifestations of motor activity and on the emotional components of motor behavior, in particular, on aggressive reactions.
The main mediators of the basal ganglia are: dopamine (especially in the substantia nigra) and acetylcholine. The defeat of the basal ganglia causes slow writhing involuntary movements, against which sharp muscle contractions occur. Involuntary jerky movements of the head and limbs. Parkinson's disease, the main symptoms of which are tremor (trembling) and muscle rigidity (a sharp increase in the tone of the extensor muscles). Due to rigidity, the patient can hardly start moving. Constant tremor interferes with small movements. Parkinson's disease occurs when the substantia nigra is damaged. Normally, the substantia nigra has an inhibitory effect on the caudate nucleus, putamen, and globus pallidus. When it is destroyed, the inhibitory influences are eliminated, as a result of which the excitatory basal ganglia increase on the cerebral cortex and reticular formation, which causes the characteristic symptoms of the disease.
limbic system
The limbic system is represented by the divisions of the new cortex (neocortex) and the diencephalon located on the border. It combines complexes of structures of different phylogenetic age, some of which are cortical, and some are nuclear.
The cortical structures of the limbic system include the hippocampal, parahippocampal, and cingulate gyrus (old cortex). The ancient cortex is represented by the olfactory bulb and olfactory tubercles. The neocortex is part of the frontal, insular, and temporal cortices.
The nuclear structures of the limbic system combine the amygdala and septal nuclei and the anterior thalamic nuclei. Many anatomists classify the preoptic region of the hypothalamus and the mammillary bodies as part of the limbic system. The structures of the limbic system form 2-way connections and are connected with other parts of the brain.
The limbic system controls emotional behavior and regulates the endogenous factors that provide motivation. Positive emotions are associated predominantly with excitation of adrenergic neurons, and negative emotions, as well as fear and anxiety, are associated with a lack of excitation of noradrenergic neurons.
The limbic system is involved in the organization of orienting-exploratory behavior. Thus, “novelty” neurons were found in the hippocampus, which change their impulse activity when new stimuli appear. The hippocampus plays an essential role in maintaining the internal environment of the body, is involved in the processes of learning and memory.
Consequently, the limbic system organizes the processes of self-regulation of behavior, emotions, motivation and memory (Fig. 42).
Rice. 42. Limbic system
autonomic nervous system
The autonomic (vegetative) nervous system provides regulation of internal organs, strengthening or weakening their activity, performs an adaptive-trophic function, regulates the level of metabolism (metabolism) in organs and tissues (Fig. 43, 44).
1 - sympathetic trunk; 2 - cervicothoracic (star-shaped) node; 3 - middle cervical node; 4 - upper cervical knot; 5 - internal carotid artery; 6 - celiac plexus; 7 - superior mesenteric plexus; 8 - inferior mesenteric plexus
Rice. 43. Sympathetic part of the autonomic nervous system,
III - oculomotor nerve; YII - facial nerve; IX - glossopharyngeal nerve; X - vagus nerve.
1 - ciliary knot; 2 - pterygopalatine node; 3 - ear knot; 4 - submandibular node; 5 - sublingual node; 6 - parasympathetic sacral nucleus; 7 - extramural pelvic node.
Rice. 44. Parasympathetic part of the autonomic nervous system.
The autonomic nervous system includes parts of both the central and peripheral nervous systems. Unlike the somatic, in the autonomic nervous system, the efferent part consists of two neurons: preganglionic and postganglionic. Preganglionic neurons are located in the central nervous system. Postganglionic neurons are involved in the formation of autonomic ganglia.
The autonomic nervous system is divided into sympathetic and parasympathetic divisions.
In the sympathetic division, preganglionic neurons are located in the lateral horns of the spinal cord. The axons of these cells (preganglionic fibers) approach the sympathetic ganglia of the nervous system, located on both sides of the spine in the form of a sympathetic nerve chain.
Postganglionic neurons are located in the sympathetic ganglia. Their axons exit as part of the spinal nerves and form synapses on the smooth muscles of the internal organs, glands, vessel walls, skin and other organs.
In the parasympathetic nervous system, preganglionic neurons are located in the nuclei of the brainstem. Axons of preganglionic neurons are part of the oculomotor, facial, glossopharyngeal and vagus nerves. In addition, preganglionic neurons are also found in the sacral spinal cord. Their axons go to the rectum, bladder, to the walls of blood vessels that supply blood to the organs located in the pelvic area. Preganglionic fibers form synapses on postganglionic neurons of parasympathetic ganglia located near the effector or inside it (in the latter case, the parasympathetic ganglion is called intramural).
All parts of the autonomic nervous system are subordinate to the higher parts of the central nervous system.
Functional antagonism of the sympathetic and parasympathetic nervous systems was noted, which is of great adaptive importance (see Table 1).
SECTION I V . DEVELOPMENT OF THE NERVOUS SYSTEM
The nervous system begins to develop at the 3rd week of intrauterine development from the ectoderm (outer germ layer).
The ectoderm thickens on the dorsal (dorsal) side of the embryo. This forms the neural plate. Then the neural plate bends deep into the embryo and a neural groove is formed. The edges of the neural groove close to form the neural tube. A long hollow neural tube, lying first on the surface of the ectoderm, separates from it and plunges inward, under the ectoderm. The neural tube expands at the anterior end, from which the brain is later formed. The rest of the neural tube is transformed into the brain (Fig. 45).
Rice. 45. Stages of embryogenesis of the nervous system in a transverse schematic section, a - medullary plate; b and c - medullary groove; d and e - brain tube. 1 - horny leaf (epidermis); 2 - ganglion roller.
From the cells migrating from the side walls of the neural tube, two neural crests are laid - nerve cords. Subsequently, spinal and autonomic ganglia and Schwann cells are formed from the nerve cords, which form the myelin sheaths of nerve fibers. In addition, neural crest cells are involved in the formation of the pia mater and arachnoid. In the inner word of the neural tube, increased cell division occurs. These cells differentiate into 2 types: neuroblasts (progenitors of neurons) and spongioblasts (progenitors of glial cells). Simultaneously with cell division, the head end of the neural tube is divided into three sections - the primary cerebral vesicles. Accordingly, they are called the anterior (I bladder), middle (II bladder) and posterior (III bladder) brain. In subsequent development, the brain is divided into the terminal (large hemispheres) and diencephalon. The midbrain is preserved as a whole, and the hindbrain is divided into two sections, including the cerebellum with the bridge and the medulla oblongata. This is the 5-bladder stage of brain development (Fig. 46,47).
a - five brain pathways: 1 - first bubble (telencephalon); 2 - the second bubble (the diencephalon); 3 - third bubble (midbrain); 4- fourth bubble (medulla oblongata); between the third and fourth bubble - isthmus; b - development of the brain (according to R. Sinelnikov).
Rice. 46. Development of the brain (diagram)
A - formation of primary blisters (up to the 4th week of embryonic development). B - F - formation of secondary bubbles. B, C - the end of the 4th week; G - the sixth week; D - 8-9th weeks, ending with the formation of the main parts of the brain (E) - by the 14th week.
3a - isthmus of the rhomboid brain; 7 end plate.
Stage A: 1, 2, 3 - primary cerebral vesicles
1 - forebrain,
2 - midbrain,
3 - hindbrain.
Stage B: the forebrain is divided into hemispheres and basal nuclei (5) and diencephalon (6)
Stage B: The rhomboid brain (3a) is subdivided into the hindbrain, including the cerebellum (8), the pons (9) stage E, and the medulla oblongata (10) stage E
Stage E: the spinal cord is formed (4)
Rice. 47. Developing brain.
The formation of nerve bubbles is accompanied by the appearance of bends due to different rates of maturation of parts of the neural tube. By the 4th week of intrauterine development, the parietal and occipital flexures are formed, and during the 5th week, the pontine flexure is formed. By the time of birth, only the curvature of the brain stem is preserved almost at a right angle in the region of the junction of the midbrain and diencephalon (Fig. 48).
Lateral view illustrating kinks in the midbrain (A), cervical (B) regions of the brain, and also in the pons (C).
1 - eye bubble, 2 - forebrain, 3 - midbrain; 4 - hindbrain; 5 - auditory vesicle; 6 - spinal cord; 7 - diencephalon; 8 - telencephalon; 9 - rhombic lip. Roman numerals indicate the origin of the cranial nerves.
Rice. 48. Developing brain (from the 3rd to the 7th week of development).
At the beginning, the surface of the cerebral hemispheres is smooth. First, at 11-12 weeks of intrauterine development, the lateral sulcus (Sylvius) is laid, then the central (Rolland's) sulcus. Quite quickly, furrows are formed within the lobes of the hemispheres, due to the formation of furrows and convolutions, the area of the cortex increases (Fig. 49).
Rice. 49. Side view of the developing hemispheres of the brain.
A- 11th week. B- 16_ 17 weeks. B- 24-26 weeks. G- 32-34 weeks. D is a newborn. The formation of a lateral fissure (5), a central sulcus (7) and other furrows and convolutions is shown.
I - telencephalon; 2 - midbrain; 3 - cerebellum; 4 - medulla oblongata; 7 - central furrow; 8 - bridge; 9 - furrows of the parietal region; 10 - furrows of the occipital region;
II - furrows of the frontal region.
By migration, neuroblasts form clusters - the nuclei that form the gray matter of the spinal cord, and in the brain stem - some nuclei of the cranial nerves.
The soma of neuroblasts have a rounded shape. The development of a neuron is manifested in the appearance, growth and branching of processes (Fig. 50). A small short protrusion is formed on the neuron membrane at the site of the future axon - a growth cone. The axon is extended and nutrients are delivered to the growth cone along it. At the beginning of development, a neuron produces a larger number of processes compared to the final number of processes of a mature neuron. Some of the processes are drawn into the soma of the neuron, and the remaining ones grow towards other neurons, with which they form synapses.
Rice. 50. Development of the spindle cell in human ontogenesis. The last two sketches show the difference in the structure of these cells in a child at the age of two years and an adult.
In the spinal cord, axons are short and form intersegmental connections. Longer projection fibers are formed later. A little later than the axon, the growth of dendrites begins. All branches of each dendrite are formed from one trunk. The number of branches and the length of the dendrites does not end in the prenatal period.
The increase in brain mass in the prenatal period occurs mainly due to an increase in the number of neurons and the number of glial cells.
The development of the cortex is associated with the formation of cell layers (in the cortex of the cerebellum - three layers, and in the cortex of the cerebral hemispheres - six layers).
The so-called glial cells play an important role in the formation of the cortical layers. These cells take a radial position and form two vertically oriented long processes. Migration of neurons occurs along the processes of these radial glial cells. First, more superficial layers of the crust are formed. Glial cells also take part in the formation of the myelin sheath. Sometimes one glial cell is involved in the formation of the myelin sheaths of several axons.
Table 2 reflects the main stages in the development of the nervous system of the embryo and fetus.
Table 2.
The main stages of development of the nervous system in the prenatal period.
| Age of fetus (weeks) | Development of the nervous system |
| 2,5 | There is a neural groove |
| 3.5 | Formation of the neural tube and nerve cords |
| 4 | 3 brain bubbles are formed; nerves and ganglia are formed |
| 5 | 5 brain bubbles form |
| 6 | The meninges are outlined |
| 7 | Hemispheres of the brain reach a large size |
| 8 | Typical neurons appear in the cortex |
| 10 | The internal structure of the spinal cord is formed |
| 12 | Common structural features of the brain are formed; neuroglial cell differentiation begins |
| 16 | Distinguishable lobes of the brain |
| 20-40 | Myelination of the spinal cord begins (20 weeks), layers of the cortex appear (25 weeks), furrows and convolutions form (28-30 weeks), myelination of the brain begins (36-40 weeks) |
Thus, the development of the brain in the prenatal period occurs continuously and in parallel, however, it is characterized by heterochrony: the rate of growth and development of phylogenetically older formations is greater than that of phylogenetically younger formations.
Genetic factors play a leading role in the growth and development of the nervous system during the prenatal period. The average brain weight of a newborn is approximately 350 g.
Morpho-functional maturation of the nervous system continues in the postnatal period. By the end of the first year of life, the weight of the brain reaches 1000 g, while in an adult the weight of the brain is on average 1400 g. Consequently, the main increase in brain mass occurs in the first year of a child's life.
The increase in brain mass in the postnatal period occurs mainly due to an increase in the number of glial cells. The number of neurons does not increase, as they lose the ability to divide already in the prenatal period. The total density of neurons (the number of cells per unit volume) decreases due to the growth of the soma and processes. The number of branches increases in dendrites.
In the postnatal period, myelination of nerve fibers also continues both in the central nervous system and the nerve fibers that make up the peripheral nerves (cranial and spinal.).
The growth of the spinal nerves is associated with the development of the musculoskeletal system and the formation of neuromuscular synapses, and the growth of the cranial nerves with the maturation of the sense organs.
Thus, if in the prenatal period the development of the nervous system occurs under the control of the genotype and practically does not depend on the influence of the external environment, then in the postnatal period, external stimuli become increasingly important. Irritation of receptors causes afferent streams of impulses that stimulate the morpho-functional maturation of the brain.
Under the influence of afferent impulses, spines are formed on the dendrites of cortical neurons - outgrowths, which are special postsynaptic membranes. The more spines, the more synapses and the more involved the neuron is in information processing.
Throughout the entire postnatal ontogenesis up to the pubertal period, as well as in the prenatal period, the development of the brain occurs heterochronously. So, the final maturation of the spinal cord occurs earlier than the brain. The development of stem and subcortical structures, earlier than cortical ones, the growth and development of excitatory neurons overtakes the growth and development of inhibitory neurons. These are general biological patterns of growth and development of the nervous system.
Morphological maturation of the nervous system correlates with the features of its functioning at each stage of ontogenesis. Thus, the earlier differentiation of excitatory neurons compared to inhibitory neurons ensures the predominance of flexor muscle tone over extensor tone. The arms and legs of the fetus are in a flexed position, resulting in a posture that provides minimal volume, so that the fetus takes up less space in the uterus.
Improving the coordination of movements associated with the formation of nerve fibers occurs throughout the entire preschool and school periods, which is manifested in the consistent mastering of the posture of sitting, standing, walking, writing, etc.
An increase in the speed of movements is mainly due to the processes of myelination of peripheral nerve fibers and an increase in the speed of excitation of nerve impulses.
The earlier maturation of subcortical structures compared to cortical ones, many of which are part of the limbic structure, determines the peculiarities of the emotional development of children (the greater intensity of emotions, the inability to restrain them is associated with the immaturity of the cortex and its weak inhibitory effect).
In the elderly and senile age, anatomical and histological changes in the brain occur. Often there is atrophy of the cortex of the frontal and upper parietal lobes. The furrows become wider, the ventricles of the brain increase, the volume of white matter decreases. There is a thickening of the meninges.
With age, neurons decrease in size, while the number of nuclei in cells may increase. In neurons, the content of RNA, which is necessary for the synthesis of proteins and enzymes, also decreases. This impairs the trophic functions of neurons. It is suggested that such neurons tire faster.
In old age, the blood supply to the brain is also disturbed, the walls of blood vessels thicken and cholesterol plaques (atherosclerosis) are deposited on them. It also impairs the activity of the nervous system.
LITERATURE
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Kishsh-Sentagothai. Anatomical atlas of the human body. - Budapest, 1972. 45th ed. T. 3.
Kurepina M.M., Vokken G.G. Human anatomy. - M.: Enlightenment, 1997. Atlas. 2nd edition.
Krylova N.V., Iskrenko I.A. Brain and pathways (Human anatomy in diagrams and drawings). M.: Publishing House of the Peoples' Friendship University of Russia, 1998.
Brain. Per. from English. Ed. Simonova P.V. - M.: Mir, 1982.
Human morphology. Ed. B.A. Nikityuk, V.P. Chtetsov. - M.: Publishing House of Moscow State University, 1990. S. 252-290.
Prives M.G., Lysenkov N.K., Bushkovich V.I. Human anatomy. - L .: Medicine, 1968. S. 573-731.
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Tissue is a collection of cells and intercellular substance similar in structure, origin and functions.
Some anatomists do not include the medulla oblongata in the hindbrain, but distinguish it as an independent department.
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2 Atlas of the human nervous system structure and disorders 4th edition, revised and supplemented Edited by V.M. Astapova Yu.V. Mikadze Approved by the Ministry of Education of the Russian Federation as a textbook for students of higher educational institutions studying in the direction and specialties of psychology Moscow Psychological and Social Institute Moscow 2004
3 LBC ya6 H54 H54 Atlas “Human Nervous System. Structure and violations. Edited by V.M. Astapov and Yu.V. Mikadze. 4th edition, revised. and additional M.: PER SE, p. Reviewers: dr. psychol. sciences, prof. Khomskaya E.D. doc. biol. Sciences Fishman M.N. The atlas presents the most successful illustrations from the works of a number of foreign and domestic authors, demonstrating the structure of the human nervous system (Section I), as well as models of higher human mental functions and individual examples of their impairment in local brain lesions (Section II). The atlas can be used as a visual textbook in courses on psychology, defectology, biology, which deal with the structure of the nervous system and higher mental functions of a person. ID license from PER SE LLC, Moscow, st. Yaroslavskaya, 13, k Tel./fax: (095) Tax benefit all-Russian product classifier OK, volume 2; books, brochures. Signed for printing Format 60x90/8. Offset paper. Offset printing. Conv. oven l. 10.0 Printed at Novosti Printing House OJSC Circulation 5,000 copies. Order L(03) ISBN Astapov V.M., 2004 Mikadze Yu.V., 2004 Tertyshnaya V.V., drawings, 2004 "PER SE", original layout, design, 2004
4 HUMAN NERVOUS SYSTEM 3 Section I General ideas about the structure of the nervous system From a cytological point of view, the nervous system includes the bodies of all nerve cells, their processes (fibers, bundles formed by them, etc.), supporting cells and membranes. Neurophysiology considers the nervous system as a part of a living system that specializes in the transmission, analysis and synthesis of information, and neuropsychology as a material substrate of complex forms of mental activity that are formed on the basis of combining various parts of the brain into functional systems. The nervous system consists of central and peripheral parts. The composition of the central nervous system (CNS) includes those departments that are enclosed in the cranial cavity and the spinal canal, and the peripheral nodes and bundles of fibers that connect the central nervous system with the sense organs and various effectors (muscles, glands, etc.). The CNS, in turn, is divided into the brain, located in the skull, and the spinal cord, enclosed in the spine. The peripheral nervous system consists of the cranial and spinal nerves. In addition, there is a vegetative (autonomous) nervous system, which also has a central and peripheral sections. The autonomic nervous system is a collection of nerves and ganglions through which the heart, blood vessels, internal organs, glands, etc. are innervated. The internal organs receive dual innervation from the sympathetic and parasympathetic divisions of the autonomic nervous system. These two departments have excitatory and inhibitory influences, determining the level of activity of organs.
5 4 Mid-sagittal section of a human head
6 5 Autonomic part of the nervous system (diagram) The sympathetic section is shown in brown, and the parasympathetic section is shown in black. Prenodal fibers are shown with solid lines, postnodal fibers with dashed lines. (According to Kurepina et al.)
7 6 Most Common Anatomical Symbols A. Drawing depicting a human in a quadrupedal position so that the brain and spinal cord roots are arranged in such a way that the anterior and posterior rostral and caudal portions of these structures can be compared with their location in animals. (According to Sade et al.) B, C. Conventional brain section planes in anatomical and pathomorphological studies. and the median (sagittal) plane; b parasagittal and in the frontal (coronary) plane; d plane lying at an angle to the horizontal plane (According to Sade et al.)
8 7 Most common anatomical designations
9 8 Nervous network Anatomical and functional structure of a neuron A large neuron with many dendrites receives information through synaptic contact with another neuron (in the upper left corner). The myelinated axon forms a synaptic contact with the third neuron (below). Neuronal surfaces are shown without glial cells that surround the process directed towards the capillary (upper right). (According to Bloom)
10 9 Scheme of distribution of cellular elements of the cerebral cortex Associative connections in the cerebral cortex 1 pyramid II layer; 2-3 pyramids of the III layer; 4, 5, 17 stellate neurons; 6 pyramids of the IV layer; 7, 8, 9 pyramids of layer V; pyramids of the VI layer. (I-VI layers of the bark) (According to Lorente de No) (According to Laurente de No)
11 10 Undivided brain Shows the main structures involved in sensory processes and internal regulation, as well as the structures of the limbic system and the brain stem. (According to Bloom et al.)
12 11 The most important areas and details of the structure of the brain The left and right cerebral hemispheres, as well as a number of structures lying in the median plane, are divided in half. The internal parts of the left hemisphere are depicted as if they were completely dissected. The eye and optic nerve connect to the hypothalamus, from the lower part of which the pituitary gland departs. The pons, medulla oblongata, and spinal cord are extensions of the posterior side of the thalamus. The left side of the cerebellum is under the left cerebral hemisphere, but does not cover the olfactory bulb. The upper half of the left hemisphere is cut open so that some of the basal ganglia (shell) and part of the left lateral ventricle can be seen. (According to Bloom et al.)
13 12 Large hemispheres The figures give the names of the convolutions, and near the figures of the furrows (According to Sinelnikov)
14 13 Large hemispheres Light brown indicates the frontal, light green parietal, red occipital, dark green temporal, dark brown marginal lobes, blue old and ancient cortex, purple cerebellum and gray brainstem. The figures give the names of the convolutions, and near the figures of the furrows. (According to Sinelnikov)
15 14 Topography of the cranial nerves at the base of the skull Cranial nerves 12 paired nerves arising from the brain. I olfactory nerve (n.olfactorius); II optic nerve (n.opticus); III oculomotor nerve (n.oculomotorius); IV trochlear nerve (n.trochlearis); V trigeminal nerve (n.trigeminus); VI abducent nerve (n.abducens); VII facial nerve (n.facialis) and VIIa intermediate nerve (n.intermedius Wrisbergi); VIII vestibulocochlear nerve (n.vestibulocochlearis); IX glossopharyngeal nerve (n.glossopharyngeus); X vagus nerve (n.vagus); XI accessory nerve (n.accessorius); XII hypoglossal nerve (n.hypoglossus). Three cranial nerves are sensitive (I, II, VIII); six motor (III, IV, VI, VII, XI, XII) and three mixed (V, IX, X). (According to Badalyan)
16 15 Cytoarchitectonic fields and representation of functions in the cerebral cortex 1, 2, 3, 5, 7, 43 (partially) representation of skin and proprioceptive sensitivity; 4 motor zone; 6, 8, 9, 10 premotor and accessory motor areas; 11 representation of olfactory reception; 17, 18, 19 representation of visual reception; 20, 21, 22, 37, 41, 42, 44 representation of auditory reception; 37, 42 auditory speech center; 41 projections of the organ of Corti; 44 motor center of speech. (According to Brodman)
17 16 Development of the brain A brain of a five-week-old embryo; B the brain of a thirty-two-thirty-four-week-old fetus; in the brain of a newborn. 1 telencephalon; 2 diencephalon; 3 midbrain; 4 hindbrain; 5 medulla oblongata; 6 brain bridge; 7 cerebellum; 8 spinal cord. (According to Badalyan)
18 17 Proportions of the skull of a newborn and an adult Scheme of the timing of myelination of the main functional systems in the brain Correlation of the proportions of the skull in an embryo of five months (1), a newborn (2), a child of one year (3), an adult (4). (According to Badalyan)
19 18 Areas of cerebral vascularization Arterial blood supply to the upper lateral surface of the cerebral hemispheres. Color coding: red middle cerebral artery, blue anterior cerebral artery, green posterior cerebral artery. Arterial blood supply to the medial surface of the cerebral hemisphere. (According to Badalyan)
20 19 Areas of cerebral vascularization Arteries at the base of the brain (A). Circle of Willis and its branches (B). 1 anterior cerebral artery; 2 internal carotid artery; 3 middle cerebral artery; 4 posterior communicating artery; 5 posterior cerebral artery; 6 superior cerebellar artery; 7 basilar artery; 8 anterior inferior cerebellar artery; 9 labyrinthine artery; 10 posterior inferior cerebellar artery; 11 vertebral artery; 12 anterior spinal artery; 13 anterior communicating artery; 14 olfactory pathway; 15 optic chiasm; 16 mamillary body; 17 posterior communicating artery; 18 oculomotor nerve. (According to Duus)
21 20 The main commissures connecting the two hemispheres of the brain The large size of the corpus callosum in comparison with other connections is striking. The figure shows a section of the brain passing along the median plane. (According to Bloom et al.)
22 21 Anatomical asymmetry of the cerebral hemispheres Above: the Sylvian sulcus in the right hemisphere deviates upward at a large angle. Bottom: The back of the planum temporale is usually much larger in the left hemisphere associated with speech functions. (According to Geschwind)
23 22 HUMAN NERVOUS SYSTEM Frequency (in percent) of anatomical differences between the hemispheres Type of asymmetry Right-handed Left-handed and ambidextral Sylvian furrow is higher on the right (Galaburda, LeMay, Kemper, Geschwind, 1978) The posterior horn of the lateral ventricle is longer on the left (McRae, Branch, Milner, 1968) yes no inverse relationship yes no inverse relationship Frontal lobe wider on the right (LeMay, 1977) Occipital lobe wider on the left (LeMay, 1977) Frontal lobe protrudes on the right (LeMay, 1977) Occipital lobe protrudes on the left (LeMay, 1977) 77 10.5 12, The frequency (in percent) of anatomical differences between the hemispheres among right-handed and left-handed individuals, as well as people who equally use both hands (ambidextrous). (By Corballis)
24 23 Structures of the brain Cerebellum. A view from above; B view from below. 1 leaves of the cerebellum; 2 fissures of the cerebellum; 3 cerebellar vermis; 4 hemispheres of the cerebellum; 5 anterior lobe of the cerebellum; 6 tongue (According to Fenish and others) Scheme of the ventricles of the brain and their relationship to the surface structures of the cerebral hemispheres. and the cerebellum; b occipital pole; in the parietal pole; g frontal pole; e temporal pole; is the medulla oblongata. 1 lateral opening of the fourth ventricle (foramen of Luschka); 2 lower horn of the lateral ventricle; 3 plumbing; 4 interventricular opening; 5 anterior horn of the lateral ventricle; 6 central part of the lateral ventricle; 7 fusion of visual tubercles (massa intermedia); 8 third ventricle; 9 entrance to the lateral ventricle; 10 posterior horn of the lateral ventricle; 11 fourth ventricle (According to Sade et al.)
25 24 Structures of the brain Topographic relationships of the basal ganglia (A). Relationship of the basal ganglia to the ventricular system (B). 1 pale ball; 2 thalamus; 3 shells; 4 caudate nucleus; 5 amygdala; 6 head of the caudate nucleus; 7 subthalamic nucleus; 8 tail of the caudate nucleus; 9 lateral ventricle. (According to Duus) Lateral ventricles, left caudate and lenticular nuclei (B). 1 lateral ventricle; 2 frontal horn of the lateral ventricle; 3 occipital (posterior) horn; 4 temporal (lower) horn; 5 head of the caudate nucleus; 6 body of the caudate nucleus; 7 tail; 8 lenticular core. (According to Fenish et al.)
26 25 Corticoreticular connections A diagram of pathways of ascending activating influences; B scheme of descending influences of the cortex; Sp specific afferent pathways to the cortex with collaterals to the reticular formation. (According to Magun)
27 26 Conducting pathways and connections of the brain A radiance of the corpus callosum and girdle. B bundles of associative nerve fibers. In arcuate nerve fibers. D, E commissural bundles of fibers. 1 corpus callosum; 2 arcuate fibers of the cerebrum, connect adjacent gyrus; 3 bundles of fibers in the cingulate gyrus; 4 upper longitudinal bundle of associative fibers, starts from the frontal lobe, passes through the occipital lobe to the temporal; 5 lower longitudinal bundle, connects the temporal and occipital lobes of the hemispheres; 6 hook-shaped bundle of associative fibers, connects the lower surface of the frontal and anterior part of the temporal lobes; 7 radiance of the corpus callosum, formed by fibers connecting the cortex of the left and right hemispheres; 8 anterior commissure. (A, B, C according to Fenish and others. D, D according to Duus)
28 27 Pathways of the spinal cord and brain (According to Kurepina et al.)
29 28 Systems of connections of primary, secondary and tertiary fields of the cortex I primary (central) fields; II secondary (peripheral) fields; III tertiary fields (analyzer overlap zones). The solid line marks the systems of projection (cortical-subcortical) projection-associative and associative connections of the cortex; dotted line other links; 1 receptor; 2 effector; 3 sensory node neuron; 4 motor neuron; 5.6 switch neurons of the spinal cord and brainstem; 7 10 switching neurons of subcortical formations; 11, 14 afferent fibers from the subcortex; 13 pyramid of the V layer; 16 pyramid of sublayer III 3 ; 18 pyramids of sublayers III 2 and III 1 ; 12, 15, 17 stellate cells of the cortex. (According to Polyakov)
30 29 History of the development of ideas about the localization of mental functions A. Phrenological map of the localization of mental abilities. Given according to the modern F.A. Gallus statue. B, C. Kleist localization map. (By Luria)
31 30 Cortical projection of sensitivity and motor system The relative size of the organs reflects the area of the cerebral cortex from which the corresponding sensations and movements can be evoked. (According to Penfield)
32 31 Somatic organization of the motor and sensory areas of the human cortex
33 32 Structural-functional model of the integrative work of the brain, proposed by A.R. Luria A. The first block of regulation of general and selective non-specific activation of the brain, including the reticular structures of the brainstem, midbrain and diencephalic regions, as well as the limbic system and mediobasal regions of the cortex of the frontal and temporal lobes brain: 1 corpus callosum, 2 midbrain, 3 mediobasal parts of the right frontal lobe of the brain, 4 cerebellum, 5 reticular formation of the trunk, 6 medial parts of the right temporal lobe of the brain, 7 thalamus; B the second block for receiving, processing and storing exteroceptive information, including the main analyzer systems (visual, skin-kinesthetic, auditory), the cortical zones of which are located in the posterior sections of the cerebral hemispheres: 1 parietal region (general sensitive cortex), 2 occipital region (visual cortex) , 3 temporal region (auditory cortex), 4 central sulcus; In the third block of programming, regulation and control over the course of mental activity, including the motor, premotor and prefrontal parts of the brain with their bilateral connections: 1 prefrontal area, 2 premotor area, 3 motor area (precentral gyrus), 4 central sulcus, (According to Chomsky)
34 33 The most important parts of the brain that form the limbic system The structures of the brain that play a role in emotions Are located along the edges of the cerebral hemispheres, as if "surrounding" them. (According to Bloom et al.) Dopamine fibers from the substantia nigra and norepinephrine fibers from the locus coeruleus innervate the entire forebrain. Both of these groups of neurons, as well as some others, are part of the reticular activating system. (According to Bloom et al.)
35 34 Scheme of the limbic system A side view; B, C dorsal view: 1 supra-causal strip; 2 legs of the hippocampus; 3 medial bundle of the forebrain; 4 anterior nucleus of the thalamus; 5 olfactory bulb; 6 transparent partition; 7 interpeduncular nucleus; 8 mamilary bodies; 9 leash; 10 vault; 11 edge bundle; 12 dentate gyrus; 13 almond-shaped nucleus; 14 epiphysis. (According to Badalyan)
36 35 Visual system Auditory system Connections from the primary receptors of the retina through the transmission nuclei of the thalamus and hypothalamus to the primary visual cortex are shown. (According to Bloom et al.) Connections are shown from primary cochlear receptors through the thalamus to the primary auditory cortex. (According to Bloom et al.)
37 36 Sensations from the surface of the body Olfactory system Taste system Connections from skin receptors through the intercalary neurons of the spinal cord and thalamus to the primary sensory cortex are presented. Connections are shown from nasal mucosal receptors through the olfactory bulbs and basal forebrain nuclei to terminal points in the olfactory cortex. Connections are shown that go from the receptors of the tongue through the initial targets of the pons to the targets of the next order in the cerebral cortex. (According to Bloom et al.) (According to Bloom et al.) (According to Bloom et al.)
38 HUMAN NERVOUS SYSTEM 37 Pathways for specific types of sensory signals Modality Switching level primary (level 1) secondary (level 2) tertiary (level 3) Vision Retina Lateral geniculate body Primary visual cortex Superior colliculus colliculi Secondary visual cortex Hearing Nuclei of the cochlea Nuclei of the loop, quadrigemina and Primary auditory cortex. medial geniculate body Touch Spinal cord or brainstem Thalamus Somatosensory cortex Smell Olfactory bulb Pyriform cortex Limbic system, hypothalamus Taste Medulla oblongata Thalamus Somatosensory cortex (According to Bloom et al.) Main categories in the field of sensory processes modality and quality Modality Sensory organ Quality Receptors Vision Retina Brightness, Contrast, Rods and cones Movement, Size, Color Hearing Cochlea Pitch, Timbre Hair cells Balance Vestibular organ Gravity Macular cells Rotation Vestibular cells Touch Skin Pressure Ruffini endings Merkel discs Vibration Pacini corpuscle Taste Tongue Sweet and sour taste Taste buds at the tip of the tongue Bitter and salty taste Taste buds at the base of the tongue Smell Olfactory nerves Floral smell Olfactory receptors Fruity Musky Spicy (According to Bloom et al.)
39 38 HUMAN NERVOUS SYSTEM Comparative characteristics of some types of analyzers Analyzer Visual (constant point signal) Absolute threshold Units of measurement Approximate value Units of measurement lux 4, lux arc. min Differential threshold Approximate value 1% of the initial intensity 0.6-1.5 Degree of execution in technical systems, % 90 Auditory Dyna/cm2 0.0002 dB 0.3-0.7 9 Tactile mg/mm mg/mm2 7% of the initial intensity 1 Taste mg/l mg/l 20% of the initial concentration extremely insignificant Olfactory mg/l 0.001-1 mg/l 16 50%, the same 2.5 9% of the initial value Kinesthetic kg kg Temperature С 0 0.2-0.4 С 0 Vestibular (acceleration during rotation and rectilinear motion) m/s 2 0.1-0.12 (According to Gomezo and others)
40 40 HUMAN NERVOUS SYSTEM Sequence of processes in response to a visual stimulus Sequence of processes in response to a visual stimulus traced through the entire brain from the retina and optic tract to the visual cortex and frontal association cortex. During a motor response, if it occurs, excitation spreads from the frontal cortex to the motor cortex, is transmitted through the synapse to the motor neuron (shown on the right in an enlarged view), then goes down the brainstem and along the corresponding nerve reaches the muscle that sets the eye in motion. The neuron is surrounded by capillaries and glial cells. Many axons form synapses on the body and dendrites of the neuron. The axon is covered by a myelin sheath. (According to Bloom et al.)
41 41 Scheme of the pathways of the visual system Scheme of the pathways of the visual system: 1 field of view; 2 course of rays in the eyeball; 3 optic nerves; 4 optic chiasm; 5 visual tracts; 6 outer crankshaft; 7 superior tubercles of the quadrigemina; 8 radiant radiance (graziola beam); 9 cortical center. (According to Badalyan)
42 42 Diagram of the organ of Corti
43 43 Auditory system Auditory nerve pathways connect the cochlea of each ear with the auditory areas of the cerebral cortex. At the lowest level of the auditory system (auditory nerves and cochlear nuclei), the pathways from both ears are completely separated. (In this highly simplified diagram, the paths from the left ear are shown in bold lines, and those from the right ear in bold.) At the next level (the olive nucleus in the medulla oblongata), some nerve fibers from the right and left cochlear nuclei converge to the same neurons. These neurons, which transmit signals from both ears, are highlighted in dotted lines. At higher levels of the system, convergence consistently increases and, accordingly, the interaction between signals from both ears increases, which is reflected in the diagram by an increase in the proportion of neurons depicted by circles. Most of the nerve pathways from the cochlear nucleus go to the opposite side of the brain. 1 auditory cortex, 2 inferior colliculus, 3 auditory nerve, 4 olive nucleus, 5 cochlear nucleus, 6 left cochlea, 7 right cochlea. (According to Rosenzweig)
44 44 Types of skin receptors A Pacini body; B Meissner's body; In the nerve plexus at the base of the hair follicle; G Krause flask; D nerve plexus of the cornea. Nerve endings in the skin are receptors for touch, heat, cold, and pain. 1 free nerve endings; 2 nerve endings around the hair follicles; 3 sympathetic nerves innervating muscle fibers; 4 Ruffini endings; 5 end bulbs Krause; 6 Merkel discs; 7 Meissner's little bodies; 8 sympathetic fibers innervating the sweat gland; 9 nerve trunks; 10 sweat gland; 11 sebaceous gland. The function of each individual type of endings is still unknown. (According to Held et al.)
45 45 Scheme of the structure of the skin-kinesthetic system Efferent neurons with a long axon are presented: 1 endings of sensory and nerve fibers in the skin and muscles, 2 sensitive peripheral neurons of the intervertebral nodes, 3 switching nuclei in the medulla oblongata, 4 switching (relay) nuclei in the thalamus , 5 skin-kinesthetic zone of the cortex, 6 motor zone of the cortex, 7 path from the motor cortex to the motor "centers" of the brain and spinal cord (pyramidal path), 8 effector neuron of the spinal cord, 9 motor nerve endings in skeletal muscles. (According to Polyakov)
46 46 Map of cortical areas where tactile signals are projected from the body surface PBV mental vibrissae MB mandibular vibrissae P finger PB chin Areas of the body with a high density of sensory receptors, such as the face or fingers, have more extensive cortical projections than areas with a low density of receptors . The boundaries of these projections are somewhat different for different individuals. (According to Bloom et al.)
47 47 Normal tactile error The normal tactile error can be defined in two ways: firstly, as the average value of the minimum distance between the contacts, at which the subject feels a pair of separate pressings when the contacts are switched on simultaneously (black bars); secondly, as the average distance between the point and the real contact (white columns). As can be seen from the figure, the accuracy of touch is significantly different in different parts of the body; the greatest accuracy is observed on the lips and fingertips. (According to Geldard et al.)
48 48 Scheme of the taste system A connections and insertion systems of the taste analyzer. (According to Smirnov) B receptors of four main taste qualities. The tip of the tongue senses all four qualities to some extent, but is most sensitive to sweet and salty things. The edges of the tongue are more sensitive to sour, but they also perceive a salty taste. The base of the tongue is most sensitive to bitter. (According to Bloom et al.)
49 49 Odor reception A. According to the stereochemical theory, different olfactory nerve cells are excited by different molecules depending on the size, shape or charge of the molecule; these properties determine which of the various pits or fissures at the ends of the olfactory nerve the molecule will approach; it can be seen here that the l-menthol molecule corresponds to the deepening of the "mint" receptor site. B. The air carrying the molecules of an odorous substance is drawn into the nasal cavity and passes by three bizarre-shaped bones to the islets of the epithelium, in which the endings of numerous olfactory nerves are immersed. C. Histological section of the olfactory epithelium showing olfactory nerve cells and their processes, trigeminal nerve endings and supporting cells. (According to Eimur et al.)
50 50 Diagram of the olfactory system and its intercalary system connections 1 cingulate gyrus; 2 anterior nucleus of the thalamus; 3 brain strip; 4 end strip; 5 vault; 6 core leash; 7 columns of the vault; 8 nipple visual path; 9 mammillary body; 10 dentate gyrus; 11 temporal lobe; 12 amygdala; 13 lateral (lateral) gyrus; 14 olfactory tract; 15 olfactory bulb; 16 medial (middle) olfactory gyrus; 17 olfactory triangle; 18 anterior commissure; 19 near the olfactory circle; 20 near the corpus callosum; 21 transparent partitions. (According to Gutchin)
51 51 Course of the pyramidal tract 1 parietal-temporal-bridge path; 2 occipital-mesencephalic path; 3 front bridge path; 4 cortical-spinal tract with extrapyramidal fibers; 5 lenticular core; 6 thalamus; 7 caudate nucleus; 8 tire core; 9 red core; 10 black substance; 11 core bridge; 12 from the cerebellum (the core of the tent); 13 reticular formation; 14 lateral nucleus of the vestibule nerve; 15 tire center path; 16 olive; 17 pyramid; 18 red nuclear-spinal tract; 19 olivospinal path; 20 pre-door-spinal path; 21 lateral cortical-spinal tract; 22 reticulospinal tract; 23 occlusal-spinal tract; 24 anterior cortical-spinal tract; 25 midbrain; 26 leg of the bridge; 27 bridge; 28 medulla oblongata; 29 cross pyramids; 30 anterior central gyrus. (According to Duus)
52 52 HUMAN NERVOUS SYSTEM Section II Higher mental functions: models and examples of disorders in local brain lesions Schematic diagram of the functional system as the basis of neurophysiological architecture M dominant motivation; P memory; OA situational afferentation; PA starting afferentation; PR decision making; PD program of action; ARD acceptor of action results; EV efferent excitations; D action; Res. result; Steam. Res. result parameters; O. Aff. reverse afferentation. (According to Anokhin)
53 HUMAN NERVOUS SYSTEM 53 Visual disorders In case of damage: I optic nerve (complete blindness on the affected side); II internal parts of the chiasm (heteronymous bitemporal hemianopsia); III external chiasma (internal, nasal hemianopsia); IV optic tract (contralateral homonymous hemianopsia); V lower divisions of the Graziole bundle or gurus lingualis (contralateral upper quadrant homonymous hemianopsia); VI of the upper sections of the Graziole bundle or cuneus (contralateral homonymous hemianopsia); VII diameter beam Graziola (contralateral homonymous hemianopia with the preservation of central vision). (According to Badalyan)
54 54 Drawings of patients with visual agnosias Drawings typical for subdominant type of opto-spatial agnosia syndrome, right-handed patients with massive lesions of the posterior parts of the right hemisphere involving its parietal lobe. A: a, b, c, d independent drawing on assignment (house, face or person, chair, table); e copying (d sample) with options (I, I, III); B: a, b, c, d, e, f, g, h, the arrangement of the hands on the clock (a circle with a center and “12 o’clock” is set) according to the proposed time (indicated by numbers after completing the task). (By Kok)
55 55 Drawings of patients with visual agnosia Drawings and errors in tests with clocks, typical for the syndrome of spatial agnosia and apraxia of the dominant type, right-handed patients with massive lesions of the posterior parts of the right hemisphere involving its parietal lobe (A, B, C, D, D, E). a, b, c, d independent drawing on assignment (house, face or person, chair, table). W Arrangement of the hands on the clock (the circle, the center and "12 o'clock" are set) according to the proposed time (indicated by numbers after the task is completed). (By Kok)
56 56 Drawings of patients with visual agnosias I. Drawings of patients with damage to the right temporal lobe. Independent drawing on assignment: a, d, e house; b bicycle; in, e, w man. (According to Kok) II. Drawings of patients with lesions of the left temporal lobe. A: a, b self-drawing on assignment; c, d copying from samples; B: a, b independent drawing on assignment; in the sample, r drawing with flipping from left to right and from top to bottom. (By Kok) III. Violations of spatial representations in patient A., 16 years old (epilepsy), left-handed with familial left-handedness. (According to Simernitskaya et al.)
57 57 Drawings of patients with visual agnosias A. Changes in the signs of simultaneous agnosia and optic-motor ataxia after the administration of caffeine to B. V. (bilateral injury of the parieto-occipital region). The patient is invited to outline the figure or put a dot in its center. B. Violation of optic-motor coordination in patient R. (bilateral vascular lesion of the occipital region): a drawing and tracing figures; b letter. B. Drawings from life and from memory in a patient with agnosia for faces (according to E.S. Bain). B-noy Chern. (bilateral vascular lesion of the occipital region): a copying from the sample; b drawing the same image from memory (According to Luria)
58 58 Ignoring the left side III. Ignoring the left side when copying a pattern. (According to Badalyan) II. Crossing out points for patients with B during the rehabilitation process: 49 (a), 58 (b) and 81 days (c) after severe traumatic brain injury. (According to Dobrokhotova et al.)
59 59 Drawing of a patient with visual neglect Disturbance of perception of the left visual hemisphere in an artist who had a hemorrhage in the posterior parietal region of the right hemisphere of the brain. Self-portraits A, B, C, and D were painted 2, 2.5, 6, and 9 months after the stroke, respectively. In the first portrait, only the right half of the image was taken. Over time, the perception of the left side is gradually restored. (According to Young)
60 60 Device for conducting experiments on patients with a dissected corpus callosum Principle of operation of the Z-lens Names or images of objects are briefly presented on the right or left sides of the screen, and the objects themselves are arranged so that they can be recognized only by touch. (according to Gazzaniga) The lens is adjacent directly to the eye, and the rays of light passing through it project the image only on one half of the retina. The other eye is covered with an overlay, so that the possibility for the other hemisphere to "see" the same material is completely excluded. Therefore, the subjects can look at the image for much longer than in experiments with a tachistoscope. (According to Bloom et al.)
61 61 Drawings of a patient with depression of the right or left hemisphere Sick. Sh-va. Drawings of the patient: 1 In the normal state; 2 In a state of oppressed right hemisphere; 3 In a state of depressed left hemisphere. (According to Deglin et al.)
62 62 HUMAN NERVOUS SYSTEM Influence of commissurotomy on drawing and writing Differences between the hemispheres in visual perception Left hemisphere Right hemisphere A drawing a cube before and after commissurotomy: before surgery, the patient can draw a cube with each hand; after the operation, the drawing of the cube with the right hand was grossly disturbed; the patient is right-handed. (according to Gazzaniga and Ledoc); B "dysgraphia-discopy" syndrome and its dynamics after crossing the posterior parts of the corpus callosum. (According to Moscoviciute, etc.) Stimuli are better recognized Verbal Non-verbal Easily distinguishable Difficult to distinguish Familiar Unfamiliar Tasks are better perceived Evaluation of temporal relationships Establishment of similarity Establishment of the identity of stimuli by name Transition to verbal coding Evaluation of spatial relations Establishment of differences Establishment of the physical identity of stimuli Visual-spatial analysis Features of the processes perception Analytical perception Holistic perception Sequential (Gestalt) perception Simultaneous perception Abstract, generalized, Concrete recognition Invariant recognition Supposed morphophysiological differences Focused Diffuse representation Representation of elementary functions (According to Leushina and others)
63 63 Different types of mistakes when writing with the left and right hand I. Writing under dictation with the right hand. II. Involuntary writing (habitual words). III. Arbitrary letter. (According to Simernitskaya)
64 64 Violations of the letter Patient Kul. A. Writing letters in different conditions. B. Writing letters in alphabetical order Writing a letter included in a well-reinforced word or an automated series does not require optical-spatial analysis necessary for writing an isolated letter and is carried out based on a well-reinforced system of kinesthetic stereotypes in the patient (not affected by local brain damage) . (According to Luria et al.)
65 65 Types of sensory disturbances a neuritic type; b segmental type; in violation of sensitivity in case of damage to the visual tubercle; d polyneuritic type. When the trunk of a peripheral nerve or nerve plexus is damaged, all types of sensitivity in the zone of innervation of this nerve are disturbed (a). Multiple nerve damage (polyneuritis) causes impaired sensation in the hands and feet, similar to gloves and stockings (d). Damage to the root or intervertebral node causes a violation of all types of sensitivity in the corresponding segmental zones (b). The defeat of the visual tuberosity and the posterior central gyrus of the cerebral cortex causes the loss of all types of sensitivity on the opposite side (c). (According to Badalyan)
66 66 HUMAN NERVOUS SYSTEM Functional model of objective action (According to Gordeeva, Zinchenko)
67 HUMAN NERVOUS SYSTEM 67 Construction of movement according to H.A. Bernstein Scheme of the main centers and pathways of the brain with their distribution according to the levels "A, B, C, D, E", which provides the construction and coordination of the main movements and actions of a person. (For clarity, the true spatial arrangement of the centers of the brain is significantly distorted). (According to Naidin)
68 68 Speech regulation scheme
69 69 Lateral surface of the left hemisphere with the proposed boundaries of the "speech zones" Regions of the cortex of the left hemisphere of the brain associated with speech functions The inner region (shaded) part of the brain, lesions of which always lead to aphasia. The pathology of the surrounding part (point) also often leads to aphasia. Pathology of other zones is rarely accompanied by speech disorders. (According to Benson et al.) A "speech zone" of the cortex of the left hemisphere; a Broca's area, in Wernicke's area, with the "center" of visual representations of words (According to Dejerine), B areas of the cortex of the left hemisphere, electrical stimulation of which causes various speech disorders in the form of stopping speech, stuttering, repeating words, various motor speech defects, as well as inability to name an object. (According to Penfield and Roberts)
70 70 Location of lesions in the left hemisphere of the brain in various forms of aphasia a with sensory aphasia, b with acoustic-mnestic aphasia, c with afferent motor aphasia, d with "semantic" aphasia, e with dynamic aphasia, f with efferent motor aphasia. (by Luria)
71 71 Localization of brain lesions in various forms of agraphia, combined with aphasia I. Lesions affecting the anterior sections of the cerebral cortex. A. Agraphia, combined with Broca's aphasia. B. Agraphia, combined with transcortical motor aphasia. B. Agraphia associated with global aphasia. G. Agraphia, combined with mixed transcortical aphasia. P. Lesions of the posterior parts of the cerebral cortex. D. Agraphia, combined with Wernicke's aphasia. E. Agraphia, combined with transcortical sensory aphasia. G. Agraphia, combined with anomic aphasia. 3. Agraphia, combined with conduction aphasia. (Note the classification of aphasias accepted in foreign psychology is given.) (According to the Blackwell Dictionary)
72 72 Magnetic resonance image of the brain of a patient with Gerstmann's syndrome Localization of lesions of the cerebral cortex in alexia Foci of pathology corresponding to the three main syndromes of alexia: A in the anterior sections; B in the central departments; In the back departments. Infarction in the left angular gyrus (left hemisphere is on the right side of the photo. (According to Blackwell's Dictionary) (According to Blackwell's Dictionary)
Atlas of the human nervous system structure and disorders 4th edition, revised and supplemented Edited by V.M. Astapova Yu.V. Mikadze Approved by the Ministry of Education of the Russian Federation as
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1 “I approve” the Vice-Rector for Academic Affairs of the Vinnitsa National Medical University named after N.I. Pirogov prof. Guminsky Yu.I. CALENDAR PLAN Practical classes and lectures on human anatomy
Name: The human nervous system. Structure and violations. Atlas.
Astapov V.M., Mikadze Yu.V.
The year of publishing: 2004
The size: 13.36 MB
Format: pdf
Language: Russian
In this atlas, in the first section, beautifully executed illustrations from a number of works by domestic and foreign authors on the structure of the human nervous system are presented. The second section demonstrates models of higher mental functions and examples of their impairments in local brain lesions. The atlas is designed to be used as a visual aid in the study of disciplines that consider the issues of the structure of the NS and the higher mental activity of a person.
Name: Neurology. National leadership. 2nd edition
Gusev E.I., Konovalov A.N., Skvortsova V.I.
The year of publishing: 2018
The size: 24.08 MB
Format: pdf
Language: Russian
Description: The National Manual "Neurology" in its 2nd edition in 2018 is supplemented with up-to-date information. The book "Neurology. National Guide" contains three sections, where the modern level describes... Download the book for free
Name: Backache.
Podchufarova E.V., Yakhno N.N.
The year of publishing: 2013
The size: 4.62 MB
Format: pdf
Language: Russian
Description: The book "Back Pain" deals with such an important medical aspect of neurology as back pain. The guide discusses the epidemiology of back pain, risk factors, morphofunctional bases of pain in... Download the book for free
Name: Neurology. National leadership. Short edition.
Gusev E.I., Konovalov A.N., Gekht A.B.
The year of publishing: 2018
The size: 4.29 MB
Format: pdf
Language: Russian
Description: The book "Neurology. National leadership. Brief edition" edited by E.I. Guseva with co-authors considers the basic issues of neurology, where neurological syndromes (pain, meninge... Download the book for free
Name: amyotrophic lateral sclerosis
Zavalishin I.A.
The year of publishing: 2009
The size: 19.9 MB
Format: pdf
Language: Russian
Description: The book "Amyotrophic Lateral Sclerosis", edited by I.A. Zavalishina, considers topical issues of this pathology from the perspective of a neurologist. The issues of epidemiology, etiopathogenesis, clinical... Download the book for free
Name: Headache. Guide for doctors. 2nd edition.
Tabeeva G.R.
The year of publishing: 2018
The size: 6.14 MB
Format: pdf
Language: Russian
Description: The presented guide "Headache" considers topical issues of the topic, highlighting such aspects of the cephalgic syndrome as the classification of headache, management of patients with headache... Download the book for free
Name: Manual therapy in vertebroneurology.
Gubenko V.P.
The year of publishing: 2003
The size: 18.16 MB
Format: pdf
Language: Russian
Description: The book "Manual Therapy in Vertebroneurology" considers general issues of manual therapy, describes the technique of manual examination, clinical and diagnostic aspects of osteochondrosis and vertebrogenic... Download the book for free
Name: Neurology for General Practitioners
Ginsberg L.
The year of publishing: 2013
The size: 11.41 MB
Format: pdf
Language: Russian
Description: The practical guide "Neurology for General Practitioners" edited by Ginsberg L. examines neurological semiotics and neurological disorders in clinical practice in detail. Imagine... Download the book for free
Name: Pediatric behavioral neurology. Volume 2. 2nd edition.
Nyokiktien Ch., Zavadenko N.N.
The year of publishing: 2012
The size: 1.7 MB
Format: pdf
Language: Russian
Description: Presented book "Children's Behavioral Neurology. Volume 2. 2nd edition" by Charles Nyokiktien, edited by Zavadenko N.N. is the final edition of the two-volume study of the development and distur...
