A) Neurography – experimental technique for recording the electrical activity of individual neurons using microelectrode technology.
B) Electrocorticography - a method for studying the total bioelectrical activity of the brain removed from the surface of the cerebral cortex. The method has experimental value; it can extremely rarely be used in a clinical setting during neurosurgical operations.
IN) Electroencephalography
Electroencephalography (EEG) is a method for studying the total bioelectrical activity of the brain removed from the surface of the scalp. The method is widely used in the clinic and makes it possible to conduct a qualitative and quantitative analysis of the functional state of the brain and its reactions to stimuli.
Basic EEG rhythms:
| Name | View | Frequency | Amplitude | Characteristic |
| Alpha rhythm |  | 8-13 Hz | 50 µV | Recorded at rest and with eyes closed |
| Beta rhythm |  | 14-30 Hz | Up to 25 µV | Characteristic of a state of active activity |
| Theta rhythm | 4-7 Hz | 100-150 µV | Observed during sleep, in some diseases. | |
| Delta rhythm |  | 1-3 Hz | During deep sleep and anesthesia | |
| Gamma rhythm | 30-35 Hz | Up to 15 µV | It is registered in the anterior parts of the brain in pathological conditions. | |
| Convulsive paroxysmal waves |
Synchronization- the appearance of slow waves on the EEG, characteristic of an inactive state
Desynchronization- the appearance on the EEG of faster oscillations of smaller amplitude, which indicate a state of brain activation.
EEG technique: Using special contact electrodes fixed by a helmet to the scalp, the potential difference is recorded either between two active electrodes or between an active and inert electrode. To reduce the electrical resistance of the skin at the points of contact with the electrodes, it is treated with fat-dissolving substances (alcohol, ether), and gauze pads are moistened with a special electrically conductive paste. During EEG recording, the subject must be in a position that ensures muscle relaxation. First, background activity is recorded, then functional tests are performed (with opening and closing the eyes, rhythmic photostimulation, psychological tests). Thus, opening the eyes leads to inhibition of the alpha rhythm - desynchronization.
1. Telencephalon: general structural plan, cyto- and myeloarchitecture of the cerebral cortex (CBC). Dynamic localization of functions in KBP. The concept of sensory, motor and associative areas of the cerebral cortex.
2. Anatomy of the basal ganglia. The role of the basal ganglia in the formation of muscle tone and complex motor acts.
3. Morphofunctional characteristics of the cerebellum. Signs of its damage.
4. Methods for studying the central nervous system.
· Do the work in writing : In your protocol notebook, draw a diagram of the pyramidal (corticospinal) tract. Indicate the localization in the body of the cell bodies of neurons, the axons of which make up the pyramidal tract, and the features of the passage of the pyramidal tract through the brain stem. Describe the functions of the pyramidal tract and the main symptoms of its damage.
LABORATORY WORK
Job No. 1.
Human electroencephalography.
Using the Biopac Student Lab system, record the EEG of the subject 1) in a relaxed state with his eyes closed; 2) with eyes closed when solving a mental problem; 3) with eyes closed after a test with hyperventilation; 4) with open eyes. Assess the frequency and amplitude of the recorded EEG rhythms. In the conclusion, characterize the main EEG rhythms recorded in different states.
Job No. 2.
Functional tests to identify cerebellar lesions
1) Romberg's test. The subject, with his eyes closed, stretches his arms forward and places his feet in one line - one in front of the other. The inability to maintain balance in the Romberg position indicates an imbalance and damage to the archicerebellum - the most phylogenetically ancient structures of the cerebellum.
2) Finger test. The subject is asked to touch the tip of his nose with his index finger. The movement of the hand to the nose should be carried out smoothly, first with open, then with closed eyes. If the cerebellum is damaged (paleocerebellum disorder), the subject misses, and as the finger approaches the nose, a tremor (shaking) of the hand appears.
3) Schilber's test. The subject stretches his arms forward, closes his eyes, raises one arm vertically up, and then lowers it to the level of the other arm extended horizontally. When the cerebellum is damaged, hypermetry is observed - the hand drops below the horizontal level.
4) Test for adiadochokinesis. The subject is asked to quickly perform alternately opposite, complexly coordinated movements, for example, to pronate and supinate the hands of outstretched arms. If the cerebellum (neocerebellum) is damaged, the subject cannot perform coordinated movements.
1) What symptoms will a patient experience if a hemorrhage occurs in the internal capsule of the left half of the brain, where the pyramidal tract passes?
2) Which part of the central nervous system is affected if the patient has hypokinesia and tremor at rest?
Lesson No. 21
Lesson topic: Anatomy and physiology of the autonomic nervous system
Purpose of the lesson: Study the general principles of the structure and functioning of the autonomic nervous system, the main types of autonomic reflexes, and the general principles of nervous regulation of the activity of internal organs.
1) Lecture material.
2) Loginov A.V. Physiology with the basics of human anatomy. – M, 1983. – 373-388.
3) Alipov N.N. Fundamentals of medical physiology. – M., 2008. – P. 93-98.
4) Human physiology / Ed. G.I.Kositsky. – M., 1985. – P. 158-178.
Questions for independent extracurricular work of students:
1. Structural and functional features of the autonomic nervous system (ANS).
2. Characteristics of the nerve centers of the sympathetic nervous system (SNS), their localization.
3. Characteristics of the nerve centers of the parasympathetic nervous system (PSNS), their localization.
4. The concept of the metasympathetic nervous system; features of the structure and function of the autonomic ganglia as peripheral nerve centers for the regulation of autonomic functions.
5. Features of the influence of the SNS and PSNS on internal organs; ideas about the relative antagonism of their actions.
6. Concepts of cholinergic and adrenergic systems.
7. Higher centers for the regulation of autonomic functions (hypothalamus, limbic system, cerebellum, cerebral cortex).
· Using materials from lectures and textbooks, Fill the table "Comparative characteristics of the effects of the sympathetic and parasympathetic nervous system."
LABORATORY WORK
Work 1.
Sketching the reflex patterns of the sympathetic and parasympathetic nervous system.
In your practical work notebook, sketch out diagrams of the SNS and PSNS reflexes, indicating their constituent elements, mediators and receptors; conduct a comparative analysis of reflex arcs of autonomic and somatic (spinal) reflexes.
Work 2.
Study of the Danini-Aschner oculocardiac reflex
Methodology:
1. The subject’s heart rate in 1 minute is determined from the pulse at rest.
2. Carry out moderate pressing the subject's eyeballs with the thumb and forefinger for 20 seconds. In this case, 5 seconds after the start of pressure, the heart rate of the subject is determined by the pulse for 15 seconds. Calculate the heart rate during the test for 1 minute.
3. The subject’s heart rate for 1 minute is determined from the pulse 5 minutes after the test.
The results of the study are entered into the table:
Compare the results obtained from three subjects.
The reflex is considered positive if the subject had a decrease in heart rate by 4-12 beats per minute;
If the heart rate has not changed or decreased by less than 4 beats per minute, such a test is considered non-reactive.
If the heart rate has decreased by more than 12 beats per minute, then such a reaction is considered excessive and may indicate that the subject has severe vagotonia.
If the heart rate increases during the test, then either the test was performed incorrectly (excessive pressure) or the subject has sympathicotonia.
Draw the reflex arc of this reflex with the designation of the elements.
In the conclusion, explain the mechanism of implementation of the reflex; indicate how the autonomic nervous system affects the functioning of the heart.
To check your understanding of the material, answer the following questions:
1) How does the effect on the effectors of the sympathetic and parasympathetic nervous system change with the administration of atropine?
2) Which autonomic reflex (sympathetic or parasympathetic) takes longer and why? When answering the question, remember the type of preganglionic and postganglionic fibers and the speed of impulse transmission through these fibers.
3) Explain the mechanism of pupil dilation in humans during anxiety or pain.
4) By prolonged irritation of the somatic nerve, the muscle of the neuromuscular preparation is brought to the point of fatigue and has stopped responding to the stimulus. What will happen to it if you simultaneously start irritating the sympathetic nerve going to it?
5) Do autonomic or somatic nerve fibers have more rheobase and chronaxy? Which structures are more lability - somatic or vegetative?
6) The so-called “lie detector” is designed to check whether a person is telling the truth when answering questions asked. The principle of operation of the device is based on the use of the influence of CBP on vegetative functions and the difficulties of controlling vegetatives. Suggest parameters that this device can record
7) The animals in the experiment were administered two different drugs. In the first case, pupil dilation and skin pallor were observed; in the second case - constriction of the pupil and lack of reaction of the skin blood vessels. Explain the mechanism of action of the drugs.
Lesson No. 22
Methods for studying the central nervous system
The most widely used methods for recording the bioelectrical activity of individual neurons, the total activity of the neuronal pool or the brain as a whole (electroencephalography), computed tomography (positron emission tomography, magnetic resonance imaging), etc.
Electroencephalography - this is registration from the surface of the skin head or from the surface of the cortex (the latter in the experiment) the total electric field of brain neurons when they are excited(Fig. 82).
Rice. 82. Electroencephalogram rhythms: A – basic rhythms: 1 – α-rhythm, 2 – β-rhythm, 3 – θ-rhythm, 4 – σ-rhythm; B – reaction of EEG desynchronization of the occipital region of the cerebral cortex when opening the eyes () and restoration of the α rhythm when closing the eyes (↓)
The origin of EEG waves is not well understood. It is believed that the EEG reflects the LP of many neurons - EPSP, IPSP, trace - hyperpolarization and depolarization, capable of algebraic, spatial and temporal summation.
This point of view is generally accepted, while the participation of PD in the formation of the EEG is denied. For example, W. Willes (2004) writes: “As for action potentials, the resulting ionic currents are too weak, fast and unsynchronized to be recorded in the form of EEG.” However, this statement is not supported by experimental facts. To prove it, it is necessary to prevent the occurrence of APs of all neurons of the central nervous system and record the EEG under conditions of the occurrence of only EPSPs and IPSPs. But this is impossible. In addition, under natural conditions, EPSPs are usually the initial part of APs, so there is no reason to assert that APs do not participate in the formation of the EEG.
Thus, EEG is the registration of the total electric field of PD, EPSP, IPSP, trace hyperpolarization and depolarization of neurons.
The EEG records four main physiological rhythms: α-, β-, θ- and δ-rhythms, the frequency and amplitude of which reflect the degree of central nervous system activity.
When studying EEG, the frequency and amplitude of the rhythm are described (Fig. 83).
Rice. 83. Frequency and amplitude of the electroencephalogram rhythm. T 1, T 2, T 3 – period (time) of oscillation; number of oscillations in 1 second – rhythm frequency; A 1, A 2 – vibration amplitude (Kiroy, 2003).
Evoked potential method(EP) consists of recording changes in the electrical activity of the brain (electric field) (Fig. 84) that occur in response to irritation of sensory receptors (usual option).
Rice. 84. Evoked potentials in a person to a flash of light: P – positive, N – negative components of VP; digital indices indicate the order of positive and negative components in the composition of the VP. The start of recording coincides with the moment the light flashes (arrow)
Positron emission tomography- a method of functional isotope mapping of the brain, based on the introduction of isotopes (13 M, 18 P, 15 O) into the bloodstream in combination with deoxyglucose. The more active an area of the brain, the more it absorbs labeled glucose. The radioactive radiation of the latter is recorded by special detectors. Information from the detectors is sent to a computer, which creates “slices” of the brain at a recorded level, reflecting the uneven distribution of the isotope due to the metabolic activity of brain structures, which makes it possible to judge possible damage to the central nervous system.
Magnetic resonance imaging allows you to identify actively working areas of the brain. The technique is based on the fact that after the dissociation of oxyhemoglobin, hemoglobin acquires paramagnetic properties. The higher the metabolic activity of the brain, the greater the volumetric and linear blood flow in a given region of the brain and the lower the ratio of paramagnetic deoxyhemoglobin to oxyhemoglobin. There are many foci of activation in the brain, which is reflected in the heterogeneity of the magnetic field.
Stereotactic method. The method allows the introduction of macro- and microelectrodes and a thermocouple into various structures of the brain. The coordinates of brain structures are given in stereotaxic atlases. By means of the introduced electrodes, it is possible to record the bioelectrical activity of a given structure, irritate or destroy it; through microcannulas, chemicals can be injected into the nerve centers or ventricles of the brain; Using microelectrodes (their diameter is less than 1 μm) placed close to the cell, it is possible to record the impulse activity of individual neurons and judge the participation of the latter in reflex, regulatory and behavioral reactions, as well as possible pathological processes and the use of appropriate therapeutic effects with pharmacological drugs.
Data about brain function can be obtained through brain surgery. In particular, with electrical stimulation of the cortex during neurosurgical operations.
Questions for self-control
1. What are the three sections of the cerebellum and their constituent elements in structural and functional terms? What receptors send impulses to the cerebellum?
2. What parts of the central nervous system is the cerebellum connected to through the inferior, middle and superior peduncles?
3. With the help of what nuclei and structures of the brain stem does the cerebellum realize its regulatory influence on the tone of skeletal muscles and motor activity of the body? Is it exciting or inhibitory?
4. What cerebellar structures are involved in the regulation of muscle tone, posture and balance?
5. What structure of the cerebellum is involved in programming goal-directed movements?
6. What effect does the cerebellum have on homeostasis, how does homeostasis change when the cerebellum is damaged?
7. List the parts of the central nervous system and structural elements that make up the forebrain.
8. Name the formations of the diencephalon. What skeletal muscle tone is observed in a diencephalic animal (the cerebral hemispheres have been removed), how is it expressed?
9. What groups and subgroups are the thalamic nuclei divided into and how are they connected to the cerebral cortex?
10. What are the names of neurons that send information to specific (projection) nuclei of the thalamus? What are the names of the paths that their axons form?
11. What is the role of the thalamus?
12. What functions do the nonspecific nuclei of the thalamus perform?
13. Name the functional significance of the association zones of the thalamus.
14. Which nuclei of the midbrain and diencephalon form the subcortical visual and auditory centers?
15. In what reactions, besides regulating the functions of internal organs, does the hypothalamus take part?
16. Which part of the brain is called the higher autonomic center? What is Claude Bernard's heat shot called?
17. What groups of chemical substances (neurosecrets) come from the hypothalamus to the anterior lobe of the pituitary gland and what is their significance? What hormones are released into the posterior lobe of the pituitary gland?
18. What receptors that perceive deviations from the norm in the parameters of the internal environment of the body are found in the hypothalamus?
19. Centers for regulating what biological needs are found in the hypothalamus
20. What brain structures make up the striopallidal system? What reactions occur in response to stimulation of its structures?
21. List the main functions in which the striatum plays an important role.
22. What is the functional relationship between the striatum and the globus pallidus? What movement disorders occur when the striatum is damaged?
23. What movement disorders occur when the globus pallidus is damaged?
24. Name the structural formations that make up the limbic system.
25. What is characteristic of the spread of excitation between the individual nuclei of the limbic system, as well as between the limbic system and the reticular formation? How is this ensured?
26. From what receptors and parts of the central nervous system do afferent impulses come to various formations of the limbic system, where does the limbic system send impulses?
27. What influences does the limbic system have on the cardiovascular, respiratory and digestive systems? Through what structures are these influences carried out?
28. Does the hippocampus play an important role in short-term or long-term memory processes? What experimental fact indicates this?
29. Provide experimental evidence demonstrating the important role of the limbic system in the species-specific behavior of an animal and its emotional reactions.
30. List the main functions of the limbic system.
31. Functions of the Peipets circle and the circle through the amygdala.
32. Cerebral cortex: ancient, old and new cortex. Localization and functions.
33. Gray and white matter of the CPB. Functions?
34.List the layers of the neocortex and their functions.
35. Fields Brodmann.
36. Columnar organization of the KBP in Mountcastle.
37. Functional division of the cortex: primary, secondary and tertiary zones.
38.Sensory, motor and associative zones of the KBP.
39. What does the projection of general sensitivity in the cortex mean (Sensitive homunculus according to Penfield). Where in the cortex are these projections located?
40.What does the projection of the motor system in the cortex mean (Motor homunculus according to Penfield). Where in the cortex are these projections located?
50. Name the somatosensory zones of the cerebral cortex, indicate their location and purpose.
51. Name the main motor areas of the cerebral cortex and their locations.
52.What are Wernicke's and Broca's areas? Where are they located? What consequences are observed when they are violated?
53. What is meant by a pyramid system? What is its function?
54. What is meant by the extrapyramidal system?
55. What are the functions of the extrapyramidal system?
56. What is the sequence of interaction between the sensory, motor and associative zones of the cortex when solving problems of recognizing an object and pronouncing its name?
57.What is interhemispheric asymmetry?
58.What functions does the corpus callosum perform and why is it cut in case of epilepsy?
59. Give examples of violations of interhemispheric asymmetry?
60.Compare the functions of the left and right hemispheres.
61.List the functions of the various lobes of the cortex.
62.Where in the cortex are praxis and gnosis carried out?
63.Neurons of which modality are located in the primary, secondary and associative zones of the cortex?
64.Which zones occupy the largest area in the cortex? Why?
66. In what areas of the cortex are visual sensations formed?
67. In what areas of the cortex are auditory sensations formed?
68. In what areas of the cortex are tactile and pain sensations formed?
69.What functions will a person lose if the frontal lobes are damaged?
70.What functions will a person lose if the occipital lobes are damaged?
71.What functions will a person lose if the temporal lobes are damaged?
72.What functions will a person lose if the parietal lobes are damaged?
73. Functions of associative areas of the KBP.
74.Methods for studying the functioning of the brain: EEG, MRI, PET, evoked potential method, stereotactic and others.
75.List the main functions of the PCU.
76. What is meant by plasticity of the nervous system? Explain using the example of the brain.
77. What functions of the brain will be lost if the cerebral cortex is removed in different animals?
2.3.15 . General characteristics of the autonomic nervous system
Autonomic nervous system- this is part of the nervous system that regulates the functioning of internal organs, the lumen of blood vessels, metabolism and energy, and homeostasis.
Departments of the VNS. Currently, two divisions of the ANS are generally recognized: sympathetic and parasympathetic. In Fig. 85 presents the sections of the ANS and the innervation of its sections (sympathetic and parasympathetic) of various organs.
Rice. 85. Anatomy of the autonomic nervous system. The organs and their sympathetic and parasympathetic innervation are shown. T 1 -L 2 – nerve centers of the sympathetic division of the ANS; S 2 -S 4 - nerve centers of the parasympathetic division of the ANS in the sacral part of the spinal cord, III-oculomotor nerve, VII-facial nerve, IX-glossopharyngeal nerve, X-vagus nerve - nerve centers of the parasympathetic division of the ANS in the brain stem
Table 10 shows the effects of the sympathetic and parasympathetic divisions of the ANS on effector organs, indicating the type of receptor on the cells of the effector organs (Chesnokova, 2007) (Table 10).
Table 10. The influence of the sympathetic and parasympathetic divisions of the autonomic nervous system on some effector organs
| Organ | Sympathetic division of the ANS | Receptor | Parasympathetic division of the ANS | Receptor |
| Eye (iris) | ||||
| Radial muscle | Reduction | α 1 | ||
| Sphincter | Reduction | - | ||
| Heart | ||||
| Sinus node | Increased frequency | β 1 | Slowdown | M 2 |
| Myocardium | Promotion | β 1 | Demotion | M 2 |
| Vessels (smooth muscle) | ||||
| In the skin, in the internal organs | Reduction | α 1 | ||
| In skeletal muscles | Relaxation | β 2 | M 2 | |
| Bronchial muscles (respiration) | Relaxation | β 2 | Reduction | M 3 |
| Digestive tract | ||||
| Smooth muscle | Relaxation | β 2 | Reduction | M 2 |
| Sphincters | Reduction | α 1 | Relaxation | M 3 |
| Secretion | Decline | α 1 | Promotion | M 3 |
| Leather | ||||
| Hair muscles | Reduction | α 1 | M 2 | |
| Sweat glands | Increased secretion | M 2 |
In recent years, convincing facts have been obtained proving the presence of serotonergic nerve fibers that run as part of the sympathetic trunks and enhance contractions of the smooth muscles of the gastrointestinal tract.
Autonomic reflex arc has the same links as the arc of the somatic reflex (Fig. 83).
Rice. 83. Reflex arc of the autonomic reflex: 1 – receptor; 2 – afferent link; 3 – central link; 4 – efferent link; 5 - effector
But there are features of its organization:
1. The main difference is that the ANS reflex arc may close outside the central nervous system- intra- or extraorgan.
2. Afferent link of the autonomic reflex arc can be formed by both its own - vegetative and somatic afferent fibers.
3. Segmentation is less pronounced in the arc of the autonomic reflex, which increases the reliability of autonomic innervation.
Classification of autonomic reflexes(by structural and functional organization):
1. Highlight central (various levels) And peripheral reflexes, which are divided into intra- and extraorgan.
2. Viscero-visceral reflexes- changes in the activity of the stomach when the small intestine is filled, inhibition of the activity of the heart when the P-receptors of the stomach are irritated (Goltz reflex), etc. The receptive fields of these reflexes are localized in different organs.
3. Viscerosomatic reflexes- change in somatic activity when the sensory receptors of the ANS are excited, for example, muscle contraction, movement of the limbs with strong irritation of the gastrointestinal tract receptors.
4. Somatovisceral reflexes. An example is the Danini-Aschner reflex - a decrease in heart rate when pressing on the eyeballs, a decrease in urine formation when the skin is painfully irritated.
5. Interoceptive, proprioceptive and exteroceptive reflexes - according to the receptors of reflexogenic zones.
Functional differences between the ANS and the somatic nervous system. They are associated with the structural features of the ANS and the severity of the influence of the cerebral cortex on it. Regulation of the functions of internal organs using the VNS can be carried out with a complete disruption of its connection with the central nervous system, but less completely. The effector neuron of the ANS is located outside the CNS: either in extra- or intraorgan autonomic ganglia, forming peripheral extra- and intraorgan reflex arcs. If the connection between muscles and the central nervous system is disrupted, somatic reflexes are eliminated, since all motor neurons are located in the central nervous system.
Influence of the VNS on organs and tissues of the body not controlled directly consciousness(a person cannot voluntarily control the frequency and strength of heart contractions, stomach contractions, etc.).
Generalized (diffuse) nature of the influence in the sympathetic division of the ANS is explained by two main factors.
Firstly, most adrenergic neurons have long postganglionic thin axons that branch repeatedly in organs and form the so-called adrenergic plexuses. The total length of the terminal branches of the adrenergic neuron can reach 10-30 cm. On these branches along their course there are numerous (250-300 per 1 mm) extensions in which norepinephrine is synthesized, stored and recaptured. When an adrenergic neuron is excited, norepinephrine is released from a large number of these extensions into the extracellular space, and it acts not on individual cells, but on many cells (for example, smooth muscle), since the distance to postsynaptic receptors reaches 1-2 thousand nm. One nerve fiber can innervate up to 10 thousand cells of the working organ. In the somatic nervous system, the segmental nature of innervation ensures more accurate sending of impulses to a specific muscle, to a group of muscle fibers. One motor neuron can innervate only a few muscle fibers (for example, in the muscles of the eye - 3-6, in the muscles of the fingers - 10-25).
Secondly, there are 50-100 times more postganglionic fibers than preganglionic fibers (there are more neurons in the ganglia than preganglionic fibers). In the parasympathetic ganglia, each preganglionic fiber contacts only 1-2 ganglion cells. Slight lability of neurons of the autonomic ganglia (10-15 impulses/s) and the speed of excitation in the autonomic nerves: 3-14 m/s in preganglionic fibers and 0.5-3 m/s in postganglionic fibers; in somatic nerve fibers - up to 120 m/s.
In organs with double innervation effector cells receive sympathetic and parasympathetic innervation(Fig. 81).
Each muscle cell of the gastrointestinal tract apparently has a triple extraorgan innervation - sympathetic (adrenergic), parasympathetic (cholinergic) and serotonergic, as well as innervation from neurons of the intraorgan nervous system. However, some of them, for example the bladder, receive mainly parasympathetic innervation, and a number of organs (sweat glands, muscles that lift the hair, spleen, adrenal glands) receive only sympathetic innervation.
Preganglionic fibers of the sympathetic and parasympathetic nervous systems are cholinergic(Fig. 86) and form synapses with ganglion neurons using ionotropic N-cholinergic receptors (mediator - acetylcholine).
Rice. 86. Neurons and receptors of the sympathetic and parasympathetic nervous system: A – adrenergic neurons, X – cholinergic neurons; solid line - preganglionic fibers; dotted line - postganglionic
The receptors got their name (D. Langley) because of their sensitivity to nicotine: small doses excite ganglion neurons, large doses block them. Sympathetic ganglia located extraorganically, Parasympathetic- usually, intraorganically. In the autonomic ganglia, in addition to acetylcholine, there are neuropeptides: metenkephalin, neurotensin, CCK, substance P. They perform modeling role. N-cholinergic receptors are also localized on the cells of skeletal muscles, carotid glomeruli and the adrenal medulla. N-cholinergic receptors of the neuromuscular junction and autonomic ganglia are blocked by various pharmacological drugs. Ganglia contain intercalary adrenergic cells that regulate the excitability of ganglion cells.
Mediators of postganglionic fibers of the sympathetic and parasympathetic nervous systems are different.
There are the following methods for studying the functions of the central nervous system:
1. method cutting brain stem at various levels. For example, between the medulla oblongata and the spinal cord;
2. method extirpation(deletion) or destruction areas of the brain;
3. method irritation various parts and centers of the brain;
4. anatomical-clinical method. Clinical observations of changes in the functions of the central nervous system when any of its parts are damaged, followed by a pathological examination;
5. electrophysiological methods:
A. electroencephalography– registration of brain biopotentials from the surface of the scalp. The technique was developed and introduced into the clinic by G. Berger;
b. registration biopotentials various nerve centers; used in conjunction with the stereotactic technique, in which electrodes are inserted into a strictly defined nucleus using micromanipulators;
V. method evoked potentials, recording the electrical activity of areas of the brain during electrical stimulation of peripheral receptors or other areas.
6. method of intracerebral administration of substances using microinophoresis;
7. chronoreflexometry– determination of reflex time.
Properties of nerve centers
Nerve center(NC) is a collection of neurons in various parts of the central nervous system that provide regulation of any function of the body. For example, the bulbar respiratory center.
The following features are characteristic for the conduction of excitation through nerve centers:
1. Unilateral conduction. It goes from the afferent, through the intercalary, to the efferent neuron. This is due to the presence of interneuron synapses.
2. Central delay carrying out excitation. Those. Excitation along the NC is much slower than along the nerve fiber. This is explained by synaptic delay. Since there are most synapses in the central link of the reflex arc, the conduction speed there is the lowest. Based on this, reflex time – This is the time from the onset of exposure to a stimulus to the appearance of a response. The longer the central delay, the longer the reflex time. However, it depends on the strength of the stimulus. The larger it is, the shorter the reflex time and vice versa. This is explained by the phenomenon of summation of excitations in synapses. In addition, it is determined by the functional state of the central nervous system. For example, when the NC is tired, the duration of the reflex reaction increases.
3. Spatial and temporal summation. Time summation arises, as in synapses, due to the fact that the more nerve impulses are received, the more neurotransmitter is released in them, the higher the amplitude of excitation of postsynaptic potentials (EPSP). Therefore, a reflex reaction can occur to several successive subthreshold stimuli. Spatial summation observed when impulses from several receptor neurons go to the nerve center. When subthreshold stimuli act on them, the resulting postsynaptic potentials are summed up and a propagating AP is generated in the neuron membrane.
4. Rhythm transformation excitation - a change in the frequency of nerve impulses as they pass through the nerve center. The frequency may decrease or increase. For example, enhancing transformation(increase in frequency) due to dispersion And animation excitations in neurons. The first phenomenon occurs as a result of the division of nerve impulses into several neurons, the axons of which then form synapses on one neuron. The second is the generation of several nerve impulses during the development of an excitatory postsynaptic potential on the membrane of one neuron. Downward Transformation is explained by the summation of several EPSPs and the occurrence of one AP in the neuron.
5. Postetanic potentiation– this is an increase in the reflex reaction as a result of prolonged excitation of the neurons of the center. Under the influence of many series of nerve impulses passing at high frequency through synapses, a large amount of neurotransmitter is released at interneuron synapses. This leads to a progressive increase in the amplitude of the excitatory postsynaptic potential and long-term (several hours) excitation of neurons.
6. Aftereffect- this is a delay in the end of the reflex response after the cessation of the stimulus. Associated with the circulation of nerve impulses along closed circuits of neurons.
7. Tone of nerve centers– a state of constant increased activity. It is caused by the constant supply of nerve impulses to the NC from peripheral receptors, the stimulating influence of metabolic products and other humoral factors on neurons. For example, the manifestation of the tone of the corresponding centers is the tone of a certain muscle group.
8. Automatic(spontaneous activity) of nerve centers. Periodic or constant generation of nerve impulses by neurons that arise spontaneously in them, i.e. in the absence of signals from other neurons or receptors. It is caused by fluctuations in metabolic processes in neurons and the effect of humoral factors on them.
9. Plastic nerve centers. This is their ability to change functional properties. In this case, the center acquires the ability to perform new functions or restore old ones after damage. The plasticity of NCs is based on the plasticity of synapses and membranes of neurons, which can change their molecular structure.
10. Low physiological lability And fast fatiguability. NCs can conduct pulses of only a limited frequency. Their fatigue is explained by fatigue of synapses and deterioration of neuronal metabolism.
Inhibition in the central nervous system
Phenomenon central braking discovered by I.M. Sechenov in 1862. He removed the frog's brain hemispheres and determined the time of the spinal reflex to irritation of the paw with sulfuric acid. Then a crystal of table salt was placed on the thalamus (visual tubercles) and found that the reflex time increased significantly. This indicated inhibition of the reflex. Sechenov concluded that the overlying NCs, when excited, inhibit the underlying ones. Inhibition in the central nervous system prevents the development of excitation or weakens ongoing excitation. An example of inhibition could be the cessation of a reflex reaction against the background of the action of another, stronger stimulus.
Was originally proposed unitary chemical theory of inhibition. It was based on Dale's principle: one neuron - one transmitter. According to it, inhibition is provided by the same neurons and synapses as excitation. It was subsequently proven correct binary chemical theory. In accordance with the latter, inhibition is provided by special inhibitory neurons, which are intercalary. These are Renshaw cells of the spinal cord and Purkinje neurons. Inhibition in the central nervous system is necessary for the integration of neurons into a single nerve center.
The following are distinguished in the central nervous system: braking mechanisms:
1. Postsynaptic. It occurs in the postsynaptic membrane of the soma and dendrites of neurons, i.e. after the transmitting synapse. In these areas, specialized inhibitory neurons form axo-dendritic or axo-somatic synapses. These synapses are glycinergic. As a result of the effect of glycine on glycine chemoreceptors of the postsynaptic membrane, its potassium and chloride channels open. Potassium and chloride ions enter the neuron, and inhibition of postsynaptic potentials (IPSPs) develops. The role of chlorine ions in the development of IPSP is small. As a result of the resulting hyperpolarization, the excitability of the neuron decreases. The conduction of nerve impulses through it stops. Alkaloid strychnine can bind to glycine receptors on the postsynaptic membrane and turn off inhibitory synapses. This is used to demonstrate the role of inhibition. After the administration of strychnine, the animal develops cramps in all muscles.
2. Presynaptic braking. In this case, the inhibitory neuron forms a synapse on the axon of the neuron that approaches the transmitting synapse. Those. such a synapse is axo-axonal. The mediator of these synapses is GABA. Under the influence of GABA, chloride channels of the postsynaptic membrane are activated. But in this case, chlorine ions begin to leave the axon. This leads to a small local but long-lasting depolarization of its membrane. A significant part of the sodium channels of the membrane is inactivated, which blocks the conduction of nerve impulses along the axon, and consequently the release of the neurotransmitter at the transmitting synapse. The closer the inhibitory synapse is located to the axon hillock, the stronger its inhibitory effect. Presynaptic inhibition is most effective in information processing, since the conduction of excitation is not blocked in the entire neuron, but only at its one input. Other synapses located on the neuron continue to function.
3. Pessimal braking. Discovered by N.E. Vvedensky. Occurs at a very high frequency of nerve impulses. A persistent, long-term depolarization of the entire neuron membrane and inactivation of its sodium channels develops. The neuron becomes unexcitable.
Both inhibitory and excitatory postsynaptic potentials can simultaneously arise in a neuron. Due to this, the necessary signals are isolated.
There are the following methods for studying the functions of the central nervous system:
1. Method of cutting the brain stem at various levels. For example, between the medulla oblongata and the spinal cord.
2. Method of extirpation (removal) or destruction of parts of the brain.
3. Method of irritating various parts and centers of the brain.
4. Anatomical and clinical method. Clinical observations of changes in the functions of the central nervous system when any of its parts are affected, followed by a pathological examination.
5. Electrophysiological methods:
A. electroencephalography - registration of brain biopotentials from the surface of the scalp. The technique was developed and introduced into the clinic by G. Berger.
b. registration of biopotentials of various nerve centers; used in conjunction with stereotactic technique, in which electrodes are inserted into a strictly defined nucleus using micromanipulators.
V. evoked potential method, recording the electrical activity of brain areas during electrical stimulation of peripheral receptors or other areas;
6. method of intracerebral administration of substances using microinophoresis;
7. chronoreflexometry - determination of reflex time.
Properties of nerve centers
The nerve center (NC) is a collection of neurons in various parts of the central nervous system that provide regulation of any function of the body. For example, the bulbar respiratory center.
The following features are characteristic for the conduction of excitation through nerve centers:
1. Unilateral conduction. It goes from the afferent, through the intercalary to the efferent neuron. This is due to the presence of interneuron synapses.
2. Central delay in the conduction of excitation. Those. Excitation along the NC is much slower than along the nerve fiber. This is explained by synaptic delay. Since there are most synapses in the central link of the reflex arc, the conduction speed there is the lowest. Based on this, reflex time is the time from the onset of exposure to the stimulus to the appearance of the response. The longer the central delay, the longer the reflex time. However, it depends on the strength of the stimulus. The larger it is, the shorter the reflex time and vice versa. This is explained by the phenomenon of summation of excitations in synapses. In addition, it is determined by the functional state of the central nervous system. For example, when the NC is tired, the duration of the reflex reaction increases.
3. Spatial and temporal summation. Temporal summation occurs, as in synapses, due to the fact that the more nerve impulses arrive, the more neurotransmitter is released in them, the higher the EPSP amplitude. Therefore, a reflex reaction can occur to several successive subthreshold stimuli. Spatial summation is observed when impulses from several neuron receptors go to the nerve center. When subthreshold stimuli act on them, the resulting postsynaptic potentials are summed up and a propagating AP is generated in the neuron membrane.
4. Transformation of the rhythm of excitation - a change in the frequency of nerve impulses when passing through the nerve center. The frequency may decrease or increase. For example, increasing transformation (increase in frequency) is due to the dispersion and multiplication of excitation in neurons. The first phenomenon occurs as a result of the division of nerve impulses into several neurons, the axons of which then form synapses on one neuron (Figure). Second, the generation of several nerve impulses during the development of an excitatory postsynaptic potential on the membrane of one neuron. The downward transformation is explained by the summation of several EPSPs and the appearance of one AP in the neuron.
5. Post-tetanic potentiation is an increase in the reflex response as a result of prolonged excitation of the neurons of the center. Under the influence of many series of nerve impulses passing at high frequency through synapses. A large amount of neurotransmitter is released at interneuron synapses. This leads to a progressive increase in the amplitude of the excitatory postsynaptic potential and long-term (several hours) excitation of neurons.
6. Aftereffect is a delay in the end of the reflex response after the cessation of the stimulus. Associated with the circulation of nerve impulses along closed circuits of neurons.
7. The tone of the nerve centers is a state of constant increased activity. It is caused by the constant supply of nerve impulses to the NC from peripheral receptors, the stimulating influence of metabolic products and other humoral factors on neurons. For example, a manifestation of the tone of the corresponding centers is the tone of a certain muscle group.
8. Automaticity or spontaneous activity of nerve centers. Periodic or constant generation of nerve impulses by neurons that arise spontaneously in them, i.e. in the absence of signals from other neurons or receptors. It is caused by fluctuations in metabolic processes in neurons and the effect of humoral factors on them.
9. Plasticity of nerve centers. This is their ability to change functional properties. In this case, the center acquires the ability to perform new functions or restore old ones after damage. The basis of plasticity N.Ts. lies the plasticity of synapses and membranes of neurons, which can change their molecular structure.
10. Low physiological lability and fatigue. N.Ts. can conduct pulses of only a limited frequency. Their fatigue is explained by fatigue of synapses and deterioration of neuronal metabolism.
Inhibition in the central nervous system
The phenomenon of central inhibition was discovered by I.M. Sechenov in 1862. He removed the frog's brain hemispheres and determined the time of the spinal reflex to irritation of the paw with sulfuric acid. Then to the thalamus, i.e. visual tubercles applied a crystal of table salt and found that the reflex time increased significantly. This indicated inhibition of the reflex. Sechenov concluded that the overlying N.Ts. when excited, they inhibit the underlying ones. Inhibition in the central nervous system prevents the development of excitation or weakens ongoing excitation. An example of inhibition could be the cessation of a reflex reaction against the background of the action of another, stronger stimulus.
Initially, a unitary-chemical theory of inhibition was proposed. It was based on Dale's principle: one neuron - one transmitter. According to it, inhibition is provided by the same neurons and synapses as excitation. Subsequently, the correctness of the binary chemical theory was proven. In accordance with the latter, inhibition is provided by special inhibitory neurons, which are intercalary. These are Renshaw cells of the spinal cord and Purkinje neurons. Inhibition in the central nervous system is necessary for the integration of neurons into a single nerve center.
The following inhibitory mechanisms are distinguished in the central nervous system:
1. Postsynaptic. It arises in the postsynaptic membrane of the soma and dendrites of neurons. Those. after the transmitting synapse. In these areas, specialized inhibitory neurons form axo-dendritic or axo-somatic synapses (Fig.). These synapses are glycinergic. As a result of the effect of GLI on glycine chemoreceptors of the postsynaptic membrane, its potassium and chloride channels open. Potassium and chloride ions enter the neuron, and IPSP develops. The role of chlorine ions in the development of IPSP is small. As a result of the resulting hyperpolarization, the excitability of the neuron decreases. The conduction of nerve impulses through it stops. The alkaloid strychnine can bind to glycine receptors on the postsynaptic membrane and turn off inhibitory synapses. This is used to demonstrate the role of inhibition. After the administration of strychnine, the animal develops cramps in all muscles.
2. Presynaptic inhibition. In this case, the inhibitory neuron forms a synapse on the axon of the neuron that approaches the transmitting synapse. Those. such a synapse is axo-axonal (Fig.). The mediator of these synapses is GABA. Under the influence of GABA, chloride channels of the postsynaptic membrane are activated. But in this case, chlorine ions begin to leave the axon. This leads to a small local but long-lasting depolarization of its membrane. A significant part of the sodium channels of the membrane is inactivated, which blocks the conduction of nerve impulses along the axon, and consequently the release of the neurotransmitter at the transmitting synapse. The closer the inhibitory synapse is located to the axon hillock, the stronger its inhibitory effect. Presynaptic inhibition is most effective in information processing, since the conduction of excitation is not blocked in the entire neuron, but only at its one input. Other synapses located on the neuron continue to function.
3. Pessimal inhibition. Discovered by N.E. Vvedensky. Occurs at a very high frequency of nerve impulses. A persistent, long-term depolarization of the entire neuron membrane and inactivation of its sodium channels develops. The neuron becomes unexcitable.
Both inhibitory and excitatory postsynaptic potentials can simultaneously arise in a neuron. Due to this, the necessary signals are isolated.
Related information.
Doppler ultrasound of extracranial vessels- study of the condition of the carotid and vertebral arteries. Provides information important for diagnosis and treatment in case of cerebrovascular insufficiency, various types of headaches, dizziness (especially associated with turning the head) or instability when walking, attacks of falls and/or loss of consciousness.
Transcranial Doppler ultrasound- a method for studying blood flow in the vessels of the brain. Used in diagnosing the condition of cerebral vessels, the presence of vascular anomalies, impaired outflow of venous blood from the cranial cavity, identifying indirect signs of increased intracranial pressure
Doppler ultrasound of peripheral vessels- study of blood flow in the peripheral vessels of the arms and legs. The study is informative for complaints of pain in the extremities during exercise and lameness, chilliness in the arms and legs, changes in the color of the skin of the arms and legs. Helps in the diagnosis of obliterating diseases of the vessels of the extremities, venous pathology (varicose and post-thrombophlebitis diseases, incompetence of venous valves).
Ultrasound Dopplerography of the ocular vessels- allows you to assess the degree and nature of blood flow disturbances in the fundus during blockage of the arteries of the eye, with hypertension, and with diabetes mellitus.
Ultrasound diagnosis of vascular diseases using duplex scanning is a fast, highly informative, absolutely safe, non-invasive research method. Duplex scanning is a method that combines the capabilities of visualizing vascular structures in real time with the characteristics of blood flow in a given vessel under study. This technology in some cases can exceed the accuracy of X-ray contrast angiography.
DS most widely used in the diagnosis of diseases of the branches of the aortic arch and peripheral vessels. Using the method, you can evaluate the condition of the vascular walls, their thickness, narrowing and degree of narrowing of the vessel, the presence of inclusions in the lumen, such as a blood clot, atherosclerotic plaque. The most common cause of narrowing of the carotid arteries is atherosclerosis, less often - inflammatory diseases; Congenital anomalies of vascular development are also possible. Of great importance for the prognosis of atherosclerotic lesions of cerebral vessels and the choice of treatment is the determination of the structure of the atherosclerotic plaque - whether it is relatively “stable”, dense or unfavorable, “soft”, which is a source of embolism.
DS allows you to assess the blood circulation of the lower extremities, the sufficiency of blood inflow and venous outflow, the condition of the valvular apparatus of the veins, the presence of varicose veins, thrombophlebitis, the condition of the compensation system, etc.
Echo-encephalography- a method of studying the brain using ultrasound. The study allows us to determine gross displacements of the midline structures of the brain, expansion of the cerebral ventricles, and identify signs of intracranial hypertension. The advantages of the method are complete safety, non-invasiveness, high information content for diagnosing intracranial hypertension, possibility and convenience for dynamic studies, and use for assessing the effectiveness of therapy.
Electroencephalography (EEG). EEG is a method of recording the bioelectrical activity of the brain. Electroencephalography(EEG) often plays a decisive role in the diagnosis of diseases manifested by attacks of loss of consciousness, convulsions, falls, fainting, and vegetative crises.
EEG is necessary in the diagnosis of diseases such as epilepsy, narcolepsy, paroxysmal dystonia, panic attacks, hysteria, and drug intoxication.
EEG Power Spectral Analysis- quantitative analysis of the state of bioelectrical activity of the brain, associated with the ratio of various rhythmic components and determination of their individual severity. This method allows you to objectively assess the characteristics of the functional state of the brain, which is important when clarifying the diagnosis, prognosis of the course of the disease and developing treatment tactics for the patient.
EEG mapping- graphical display of the power distribution of dynamic electric fields reflecting the functioning of the brain. In a number of diseases, bioelectrical activity can change in strictly defined areas of the brain, the ratio of activity of the right and left hemispheres, the anterior and posterior parts of the brain responsible for different functions is disrupted. EEG mapping helps the neurologist to gain a more complete understanding of the participation of individual brain structures in the pathological process and the disruption of their coordinated activity.
Our clinic for diagnostics (research) of the nervous system has a new portable sleep research system "Embletta" (Iceland). This system allows you to record snoring, breathing, movement of the chest and abdominal walls, blood oxygen saturation and objectively determine whether there are pauses in breathing during sleep. Unlike other sleep study methods, you will not need to travel to a special sleep laboratory to conduct this study. A specialist from our clinic will come to your home and install the system in a familiar and comfortable environment for you. The system itself will record your sleep indicators without the participation of a doctor. When there are no distractions, your sleep is closest to normal, which means you will be able to register all the symptoms that worry you. When identifying signs of sleep apnea syndrome, the most effective treatment is by creating continuous positive pressure in the airways. The method is called CPAP therapy (an abbreviation of the English words Continuous Positive Airway Pressure - constant positive pressure in the respiratory tract).
Slow potentials- a method that allows you to get an idea of the level of energy expenditure of the brain. The method is important when examining patients with muscular dystonia, Parkinson's disease, chronic cerebrovascular insufficiency, asthenia, and depression.
Evoked potentials of the brain - evoked potentials (EP) - bioelectrical activity of the brain that occurs in response to the presentation of visual, auditory stimuli, or in response to electrical stimulation of peripheral nerves (median, tibial, trigeminal, etc.).
Accordingly, visual EPs, auditory EPs and somatosensory EPs are distinguished. Registration of bioelectrical activity is carried out by surface electrodes applied to the skin in various areas of the head.
Visual VPs - make it possible to assess the functional state of the visual pathway along the entire length from the retina to the cortical representation. VEPs are one of the most informative methods for diagnosing multiple sclerosis, damage to the optic nerve of various etiologies (inflammation, tumor, etc.).
Visual evoked potentials are a research method that allows you to study the visual system, determine the presence or absence of damage from the retina to the cerebral cortex. This study helps in the diagnosis of multiple sclerosis, retrobulbar neuritis, etc., and also allows us to determine the prognosis of visual impairment in diseases such as glaucoma, temporal arteritis, diabetes mellitus and some others.
Auditory VPs- allow you to test the function of the auditory nerve, as well as accurately localize the lesion in the so-called stem cerebral structures. Pathological changes in EP of this modality are found in multiple sclerosis, tumors of deep localization, acoustic neuritis, etc.
Auditory evoked potentials - method for studying the auditory system. The information obtained through this method has great diagnostic value, as it makes it possible to determine the level and nature of damage to the auditory and vestibular system along its entire length from the ear receptors to the cerebral cortex. This study is necessary for people suffering from dizziness, hearing loss, noise and ringing in the ears, and vestibular disorders. The method is also useful in examining patients with pathologies of the ENT organs (otitis media, otosclerosis, sensorineural hearing loss)
Somatosensory EPs- contain valuable information about the conductive function of the pathways of the so-called somatosensory analyzer (receptors of muscles and joints, etc.). The use of this technique is most justified when diagnosing damage to the central nervous system (for example, multiple sclerosis), as well as damage to the brachial plexus.
Evoked somatosensory potentials - the method allows you to study the state of the sensitive system from the receptors of the skin of the hands and feet to the cerebral cortex. Plays an important role in the diagnosis of multiple sclerosis, funicular myelosis, polyneuropathy, Strumpel's disease, and various diseases of the spinal cord. The method is important in excluding a severe progressive disease - amyotrophic lateral sclerosis. This study is necessary for people with complaints of numbness in the arms and legs, impaired pain, temperature and other types of sensitivity, instability when walking, and dizziness.
Trigeminal VPs- (with stimulation of the trigeminal nerve) are a recognized method for assessing the functional state of the trigeminal nerve system. The study of trigeminal VP is indicated for neuropathy, trigeminal neuralgia, and headaches.
Trigeminal evoked potentials- study of the trigeminal nerve system - the nerve that provides sensitivity in the face and head. The method is informative in cases of suspected diseases such as trigeminal neuropathy (traumatic, infectious, compression, dysmetabolic origin), trigeminal neuralgia, and is also valuable in the study of patients with neurodental disorders, migraines, and facial pain.
Evoked cutaneous sympathetic potentials- a method for studying the state of the autonomic nervous system. The ANS is responsible for functions such as sweating, vascular tone, respiratory rate and heart rate. Its functions can be impaired either in the direction of decreasing its activity or increasing it. This is important in the diagnosis and treatment of autonomic disorders, which can be a manifestation of both primary (benign, inorganic) diseases (for example, local palmar hyperhidrosis, Raynaud's disease, orthostatic syncope) and serious organic diseases (Parkinson's disease, syringomyelia, vascular myelopathy ).
Transcranial magnetic stimulation- a method for studying various levels of the nervous system responsible for movement and strength, allows you to identify disorders from the cerebral cortex to the muscles, and assess the excitability of nerve cells in the cerebral cortex. The method is used in the diagnosis of multiple sclerosis and movement disorders, as well as for an objective assessment of the degree of damage to the motor pathways during paresis and paralysis (after a stroke, spinal cord injury).
Determination of conduction velocity along motor nerves- a study that provides information about the integrity and function of the peripheral motor nerves of the arms and legs. It is performed for patients who complain of decreased strength/weakness in muscles or muscle groups, which may be a consequence of damage to peripheral motor nerves when they are compressed by spasmodic muscles and/or osteoarticular structures, with polyneuropathies of various origins, and with limb injuries. The results of the study help develop treatment tactics and determine indications for surgical intervention.
Determination of conduction velocity along sensory nerves- a technique that allows you to obtain information about the integrity and functions of the peripheral sensory nerves of the arms and legs, identify hidden disorders (when there are no symptoms of the disease), determine indications for preventive therapy, and in some cases, exclude the organic nature of the disease. It is extremely important in the diagnosis of neurological manifestations and complications of diabetes mellitus, alcoholism, chronic and acute intoxication, viral damage to peripheral nerves, metabolic disorders and some other pathological conditions. The study is carried out for patients who complain of numbness, burning, tingling and other sensory disturbances in the arms and legs.
Blink reflex- the study is carried out to assess the speed of impulses in the trigeminal-facial nerve system, in order to study the functional state of the deep structures (stem) of the brain. The method is indicated for people suffering from facial pain, suspected damage to the trigeminal or facial nerves, or neurodental problems.
Exteroceptive suppression of voluntary muscle activity- the method is based on the assessment of the trigeminal-trigeminal reflex, which makes it possible to examine the sensory and motor fibers of the trigeminal nerve and the associated brain structures. The method is highly informative for diseases of the trigeminal nerve, facial and headaches, other chronic pain syndromes including pathology of the temporomandibular joint, as well as various polyneuropathies.
Electroneuromyography (ENMG). Electroneuromyography is a study of the biopotentials of muscles (nerves) using special electrodes at rest and during functional activation.
Electroneuromyography refers to electrodiagnostic studies and is in turn divided into needle EMG, stimulation EMG and electroneurography. The method makes it possible to diagnose diseases of the peripheral nervous system, manifested by numbness, pain in the limbs, weakness, increased muscle fatigue, and paralysis. ENMG is also informative for a number of other diseases: neuritis of the trigeminal, facial nerves, facial hemispasm, etc.
Study of F-wave, H-reflex- special methods for assessing the integrity and functions of spinal cord segments, spinal nerve roots, nerve fibers responsible for maintaining muscle tone. These studies are used for the objective diagnosis of radicular syndromes (so-called “radiculitis”), compression of the spinal nerves, increased muscle tone (eg, spasticity after a stroke, rigidity in Parkinson’s disease).