Neurophysiological research methods in neurology. Introduction to Clinical Neurophysiology

61 school-age patients were observed after a concussion. Observations were carried out at different periods of injury: in the acute period, 3-6 months and more than one year after injury. A clinical neurological examination was carried out, neurophysiological (evoked potentials, electroencephalogram) and neuropsychological research methods were used. The functional state of the central nervous system was assessed. The study made it possible to note that the most significant clinical and neurophysiological changes were observed 3-6 months after neurotrauma. The indicators of evoked potentials were clarified, where an extension of the latent period and a change in amplitude were noted. Recovery of indicators is observed only a year after the injury. The results of the study can be used to clarify the dynamics of restoration of neurophysiological processes in the long-term period of traumatic brain injury.

neurotrauma

traumatic brain injury

evoked potentials

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Introduction

Pediatric traumatic brain injury (TBI) occupies a special place among childhood neurotraumatism. According to foreign authors (Sarah J. Gaskill, Arthur E. Merlin, 1993), head injury is the main cause of death in children over 1 year of age. According to domestic researchers (Krasnov A.F., Sokolov V.A., 1995), neurotrauma among children occurs in 25-45% of cases. In most cases, with pediatric TBI, problems remain in objectively diagnosing the severity of the injury. In this regard, it was of interest to clinically and neurophysiologically assess the functional state of the brain of adolescent children who had suffered a TBI.

Purpose The present study was to evaluate the dynamics of neurophysiological parameters during different periods of TBI in children.

Material and methods

61 schoolchildren who had suffered a TBI in the form of a mild brain contusion (according to the classification of Konovalov A.N., Likhterman B.N., 2006) were under observation in a hospital at the age of 13-16 years. Among them are 39 boys and 22 girls. In 36% of cases, TBI occurred without loss of consciousness in the victims. A clinical and neurophysiological examination was carried out using EEG in the acute period of TBI, 3-6 months and more than one year after the injury and the method of visual evoked potentials (VEP) for a flash in the acute period. EEG was performed on 46 children during the acute period. The control group consisted of 13 practically healthy children of the same age. After 3-6 months, 34 children were examined, and a year later - 27 children. VZP was performed on 38 victims. The studies were carried out on a device manufactured by NeuroSoft with computer processing, developed at the Academy of Medical Sciences of the Russian Federation in Ivanovo.

EEG was recorded on a 21-channel electroencephalograph. Visual and computer analysis of 16 monopolar leads was carried out using standard methods. The VZP method, which allows for a quantitative assessment of the visual analyzer, was carried out according to standard methods. The emphasis was primarily on studying the main component P2 with a latency of about 100 ms (P100) and an amplitude N1 - P2 of the order of 10 μV.

Research results and discussion

A neurological examination revealed the following syndromes: autonomic dystonia, cerebral syndrome and syndrome of diffuse cerebral microsymptoms and their combination.

Whole-brain syndrome (CM) was established in 31 (50.8%) victims. Disseminated cerebral microsymptoms syndrome (MCMS) was diagnosed in 22 (36.1%) cases. Autonomic dystonia syndrome (VD) was diagnosed in 8 (13.3%) children.

In our work, we used the most common method for assessing EEG changes, namely descriptive-visual. According to EEG data, all patients with OM syndrome in the acute period of TBI showed changes in the main EEG rhythms, taking into account age-related characteristics. The EEG recorded diffuse disturbances of cortical rhythms with a decrease in the regularity of the basic physiological rhythm. Interzonal differences had a pronounced tendency to smooth out with increasing power in the β-band of the frequency spectrum. Pathological changes manifested themselves in the form of uneven amplitudes and periods of alpha waves, more pronounced disturbances in modulation and spatial distribution of amplitude indicators, and an increase in rhythm frequency by 1.9 times. Photostimulation caused desynchronization of the main EEG rhythms, which in turn indicates an increase in cortical activation processes.

VZP data in the acute period with cerebral syndrome (n=19) for the most constant indicator P2 (P100) revealed significant (p<0,05) увеличение латентного периода справа и слева в сравнении с контрольной группой (Р2 - 117,3±2,65 мкВ слева; 119,3±2,32 мкВ справа;). Амплитудный анализ волны Р2 показал, что в остром периоде имело место достоверное (р<0,05) усиление силы ответа слева и справа на предъявляемый стимул (соответственно- 10,7±1,49 мв и 11,1±1,62 мв).

In patients with RCMS syndrome, the EEG was dominated by slow-wave activity in the θ- and δ-bands with overlapping α- and β-activity. Spontaneous power patterns of different frequency ranges were recorded. In this group of patients, bursts of generalized bilateral synchronous θ- and δ-waves were more often noted. These outbreaks occurred constantly, intensifying during stress tests (hyperventilation), or occurred periodically. This pathological activity is more regular and symmetrical, the lower in the trunk the pathological focus is localized. In this group, the VZP data (n=13) were the most pronounced in terms of the main indicators and significantly (p<0,05) отличались от таковых контрольной группы. Полученные данные отражали наиболее выраженные изменения латентного периода (Р2 - 122,4±2,73 слева; 127,3±3,8 справа) в сравнении с другими синдромами. Данные ЭЭГ и ВЗП в определенной мере согласуются с клиническими проявлениями, учитываемые при данном синдроме с учетом вовлеченных структур в патологический процесс.

Amplitude analysis of the P2 wave in this group of patients showed that in the acute period there was an increase in the strength of the response to the presented stimulus (12.0±1.33 on the left; 12.9±1.03 on the right; control - 9.4±0.71 left). It should be noted that in this syndrome this indicator was the most pronounced, which indicated irritation of the cortex and structures that form the response to the presented stimulus. In some cases, there were additional waves at the bottom of the wave. In 2 cases, the peak of the wave split in the form of a “W”, which indicates axonal damage to the existing disorders.

Changed EEG parameters in patients in this group were also recorded after 3 months. after TBI in the form of rare bursts of generalized bilateral synchronous θ- and δ-waves, smoothing of zonal differences. In 4 patients, the rhythmic state remained virtually unchanged compared to the acute period, which was also compared with clinical data, where there were complaints of periodic feelings of nausea during physical activity, fatigue, sleep disturbance, and memory loss.

In VD syndrome, EEG changes were not primarily in the nature of increasing dysfunction of mesencephalic structures. In this group, the EEG recorded diffuse disturbances of cortical rhythms with a decrease in the regularity of the main physiological rhythms. The smoothing of interzonal differences was less noticeable in these patients. Rare patterns of slow-wave activity with increased spectral power, occurring predominantly during hyperventilation, were recorded. Photostimulation in the low frequency spectrum (5Hz, 7Hz) did not lead to significant changes in the EEG. Quantitative characteristics according to VZP data (n=14) in this syndrome revealed an increase in the latent period in comparison with the control (P2 - 110.1±3.92 on the left; 111.4±2.39 on the right). From the data presented, in this syndrome, changes in the latent period were changed to a lesser extent in comparison with data on other syndromes.

The data obtained through combined visual and spectral analysis made it possible to identify several EEG variants, which, apparently, can be considered as correlates of different phases of the neurodynamic response of the brain to disturbances in intracranial homeostasis in TBI.

In the long-term period after the injury, pathologically altered bioelectrical activity of the brain developed mainly in the group with RCMS syndrome and OM syndrome. Mostly, these changes were presented in the form of a diffusely flattened EEG with an unclear α rhythm. Changes associated with the disruption and smoothing of the zonal distribution were also observed here. As a rule, this was combined with patient complaints of fatigue, drowsiness, and decreased concentration, which also indicated the inferiority of activating nonspecific midline brain structures with desynchronization processes. These data are also consistent with other authors.

All VZP indicators differed from the control group. The most significant changes in the acute period of TBI were the indicators of the latent period of predominantly late EP components in comparison with the control group in the group of children with RCMS syndrome.

Conclusion

A clinical and neurophysiological study of children after a TBI with mild brain contusion revealed the predominance of scattered cerebral microsymptoms and cerebral syndrome in the clinical picture. The EEG results made it possible to clarify the presence of diffuse changes in the bioelectrical activity of the brain involving predominantly stem and diencephalic structures of the brain. Data from evoked visual potentials revealed changes in EP indicators in the acute period of neurotrauma in the form of an extension of the latent period, which indicates demyelination processes and axonal disorders. The results obtained make it possible to objectify pathological changes in the central nervous system, both in acute and long-term periods of TBI.

Bibliographic link

Sergeeva V.N., Antonova E.N., Zakharyan E.S., Dauletkerieva R.R., Erkenova S.M., Kolesnikova I.G., Babayan I.V. NEUROPHYSIOLOGICAL METHODS FOR STUDYING TRANO BRAIN INJURY // Advances in modern natural science. – 2015. – No. 1-1. – P. 21-23;
URL: http://natural-sciences.ru/ru/article/view?id=34769 (access date: November 25, 2019). We bring to your attention magazines published by the publishing house "Academy of Natural Sciences"

Physiological processes, as a rule, are hidden from external observation, so for a long time they remained outside the area of interest of psychologists, who were mainly engaged in the study of manifestations of human behavior that are accessible to direct observation. However, many models of mental activity would be purely speculative if psychologists were not interested in the neurophysiological processes that underlie the reality they are studying.

On the other hand, in neurophysiology there has been a constant need to describe the organization of physiological processes in terms defined in psychological concepts and theories. There was and is a mutual enrichment of the two human sciences, both theoretical developments and experimental methods. What does the study of physiological indicators of the nervous system provide? First, physiological measures become reliable elements used in describing the behavior being studied. Secondly. It allows experimenters to include in the scope of their research manifestations of the body’s activity that are hidden from direct observation and lie at the basis of behavior.

In psychophysiology, the main methods for recording physiological processes are electrophysiological methods. The electrical component occupies a special place in the physiological activity of cells, tissues and organs. Electrical potentials reflect the physical and chemical consequences of metabolism that accompany all basic life processes, and therefore are extremely reliable, universal and accurate indicators of the course of any physiological processes.

Reliability of electrical indicators compared to others, according to A.B. Kogan is especially demonstrative “when they turn out to be the only means of detecting activity.” The uniformity of action potentials in a nerve cell, nerve fiber, and muscle cell, both in humans and in animals, indicates the universality of these indicators. Accuracy of electrical indicators, i.e. their temporal and dynamic correspondence to physiological processes is based on fast physicochemical mechanisms of potential generation. Being an integral component of physiological processes in the nervous or muscle structure.

To the listed advantages of electrical indicators of physiological activity, one should add the undeniable technical convenience of their recording: in addition to special electrodes, a universal biopotential amplifier is sufficient for this. And, what is important for psychophysiology, most of these indicators can be recorded without injuring the object in any way or interfering with the processes being studied. The most widely used methods include recording the impulse activity of nerve cells, recording the electrical activity of the skin, electroencephalography, electrooculography, electromyography and electrocardiography. Recently, a new method of recording the electrical activity of the brain has been introduced into psychophysiology - magnetoencephalography and the isotope method.

The study of the activity of nerve cells, or neurons, as integral morphological and functional units of the nervous system, of course, remains a basic direction in psychophysiology. One of the indicators of neuron activity is action potentials - electrical impulses with a duration of several ms and an amplitude of up to several mV. Modern technical capabilities make it possible to record impulse activity in animals in free behavior and, thus, compare this activity with various behavioral indicators. In rare cases, during neurosurgical operations, researchers are able to record the impulse activity of neurons in humans.

Since neurons are small in size (several tens of microns), their activity is recorded using special lead microelectrodes placed close to them. Microelectrodes are available in metal and glass. The electrode is fixed in a special micromanipulator mounted on the animal’s skull and is connected to an amplifier. Using a micromanipulator, the electrode is introduced step by step through a hole in the skull into the brain. The step length is several microns, which allows the recording tip of the electrode to be brought very close to the neuron without damaging it. The electrode is brought to the neuron either manually, in which case the animal must be at rest, or automatically at any stage of the animal’s behavior. The amplified signal is sent to the monitor and recorded on magnetic tape or in computer memory. When the tip of the electrode “approaches” the neuron, the experimenter sees on the monitor the behavior of the impulses, the amplitude of which gradually increases with further careful advance of the electrode. When the amplitude of the impulses begins to exceed background brain activity, the electrode is no longer applied to eliminate the possibility of damage to the neuron membrane.

Neurophysiological examination methods.

Treatment of headaches and other neurological diseases requires, first of all, an accurate diagnosis. It is impossible to treat correctly without making the correct diagnosis. At the initial stage of the examination, to identify the causes of headaches, dizziness, memory impairment, incoordination of movements, and the consequences of traumatic brain injury, the following diagnostic research methods are used:

Electroencephalography (EEG) is a method of recording fluctuations in electrical potentials of the brain in adults and children, recorded using special devices - electroencephalographs

The ability to assess brain activity, the presence of pathological activity, including epileptiform, monitoring the effect of anticonvulsants, studying fainting states, the degree of physiological maturity of cortical rhythms (age-appropriate) in children.

Electroencephalography - monitoring (EEG) is a method of long-term (over many hours, days) recording of EEG on a flash card with further export of the recorded information to a computer system for analysis and viewing. The method makes it possible to analyze the dynamics of the EEG during normal human life, under the influence of natural stimuli that affect a person in his daily activities, which is of great importance when examining children, as well as under the influence of various functional (photostimulation, hyperventilation, etc.) ) loads in any conditions. To carry out EEG monitoring, electrodes (19-scalp, 2-ear) are put on the patient, which are connected to a box with reference cells, which in turn is connected to the patient unit, into which 4 batteries and a flash card for recording data are pre-inserted EEG. EEG monitoring allows not only diagnosis, but also correction of treatment, prognosis of the disease, as well as differential diagnosis of numerous forms of epilepsy, non-epileptic seizures, assessment of the persistence of remission and the possibility of discontinuing therapy, etc. EEG monitoring is also used for sleep disorders: assessed depth of sleep, duration of its individual phases.

Electroencephalography with sleep deprivation (EEG with sleep deprivation) followed by short-term (20-30 min) sleep

Sleep deprivation for 24-48 hours before EEG is carried out to identify hidden epileptic activity in difficult to recognize cases of epilepsy. Sleep deprivation is a fairly strong trigger for attacks. In this case, the patient does not sleep the whole night before the procedure, and in the morning a standard EEG is performed, after which (if the patient falls asleep) a sleep EEG can be recorded for 20-30 minutes. Recording an EEG during sleep makes it possible to detect epileptic activity in the majority of those patients in whom it was not detected during the daytime, even under the influence of ordinary provocative tests.

Rheoencephalography (REG) is a method that studies volumetric fluctuations in the blood supply of the vessels of the brain and neck based on graphical recording of pulse-synchronous changes in resistance between electrodes applied to the scalp (using a rheoencephalograph)

Makes it possible to judge the tone and elasticity of the vessels of the brain and neck, blood viscosity, the speed of propagation of the pulse wave, the speed of blood flow, to evaluate latent periods, the time and severity of regional vascular reactions.

Echoencephalography (EchoEG) is an instrumental diagnostic method based on the reflection of ultrasound from the border of intracranial formations and media with different acoustic densities (soft integument of the head, skull bones, meninges, medulla, cerebrospinal fluid, blood).

The most important indicator in echoencephalography (EchoEG) is the position of the midline structures of the brain (M-echo) and the assessment of hydrocephalic-hypertensive syndrome (intracranial pressure).

Electroneuromyography is a diagnostic method that allows you to measure the speed of transmission of a nerve impulse along nerve fibers. Allows you to easily establish the “site” of damage to the nervous structures, it is used in the diagnosis of various diseases of the peripheral nervous system (mono- and polyneuropathy due to intoxication, diabetes mellitus, limb injuries with damage to peripheral nerves, etc.) We perform electroneuromyography of the upper and lower extremities with using an electroneuromyograph. The entire myography procedure takes about an hour. The patient lies down on the couch and, using a pulsed current emitter, the functional diagnostics doctor causes nerve excitation and muscle contraction.

Subject, content, significance of neurophysiology. Formation and development of science.

The word physiology comes from the Greek word fussis - the science of nature. Initially, it denoted the entire set of sciences about the plant and animal world. As knowledge accumulated, an independent scientific discipline emerged, studying the functions of a living organism, which became known as physiology.

Physiology – is the science of the functions of cells, tissues, organs, organ systems and the entire organism.

Physiology studies the processes occurring in human organs and systems, in their relationship with the environment, under various conditions of the body.

Physiology problem consists in knowing the properties, forms of manifestation and mechanisms of regulation of these properties under various states of the body and various environmental conditions.

Child physiology- a science that studies changes in body functions that occur during its development.

Neurophysiology studies the patterns of functioning of the central nervous system, the peculiarities of the functioning of central nervous system structures, and their relationship with each other.

The task of neurophysiology is to understand the mechanisms of the brain and spinal cord.

Neurophysiology closely related to Physiology of GNI. It has now been established that the substrate for the implementation of complex reflex reactions is the cerebral cortex and subcortical structures. GNI was identified as a conditioned reflex activity of the higher parts of the central nervous system, ensuring an adequate and most perfect relationship of the whole organism to the outside world. GNI – This is a set of complex forms of activity of the cerebral cortex and the subcortical formations closest to it, ensuring the relationship of the whole organism with the external environment.

In recent years, there has been a tendency in world science to integrate information obtained in related fields of knowledge and create a system of neurosciences on this basis. Neurosciences include; neurophysiology, physiology of VND and psychophysiology.

Psychology is one of the oldest sciences in the modern system of scientific knowledge. It arose as a result of man's awareness of himself. The very name of this science - psychology (psyche - soul, logoc - teaching) indicates that its main purpose is knowledge of one’s soul and its manifestations - will, perception, attention, memory, etc. Neurophysiology, a special branch of physiology that studies the activity of the nervous system, arose much later. Almost until the second half of the 19th century, neurophysiology developed as an experimental science based on the study of animals. Indeed, the “lower” (basic) manifestations of the nervous system are the same in animals and humans. Such functions of the nervous system include the conduction of excitation along a nerve fiber, the transition of excitation from one nerve cell to another (for example, nerve, muscle, glandular), simple reflexes (for example, flexion or extension of a limb), the perception of relatively simple light, sound, tactile and other irritants and many others. Only at the end of the 19th century did scientists begin to study some of the complex functions of respiration, maintaining a constant composition of blood, tissue fluid, and some others in the body. In all these studies, scientists did not find significant differences in the functioning of the nervous system, either as a whole or its parts, in humans and animals, even very primitive ones. For example, in the early days of modern experimental physiology, the frog was a favorite subject. Only with the discovery of new research methods (primarily the electrical manifestations of the activity of the nervous system) did a new stage begin in the study of the functions of the brain, when it became possible to study these functions without destroying the brain, without interfering with its functioning, and at the same time study the highest manifestations of its activities - perception of signals, functions of memory, consciousness and many others.

As already indicated, psychology as a science is much older than physiology, and for many centuries psychologists in their research did without knowledge of physiology. Of course, this is primarily due to the fact that the knowledge that physiology had 50-100 years ago concerned only the processes of functioning of the organs of our body (kidneys, heart, stomach, etc.), but not the brain. The ideas of ancient scientists about the functioning of the brain were limited only to external observations: they believed that there were three ventricles in the brain, and ancient doctors “placed” one of the mental functions in each of them (Fig. 1).

A turning point in understanding the functions of the brain came in the 18th century, when very complex clock mechanisms began to be manufactured. For example, music boxes played music, dolls danced, and played musical instruments. All this led scientists to the idea that our brain is in some way very similar to such a mechanism. Only in the 19th century was it finally established that the functions of the brain are carried out according to the reflex principle. However, the first ideas about the reflex principle of the human nervous system were formulated back in the 18th century by the philosopher and mathematician Rene Descartes. He believed that nerves were hollow tubes through which animal spirits were transmitted from the brain, the seat of the soul, to the muscles. In Fig. 2 shows that the boy burned his leg, and this stimulus triggered the entire chain of reactions: first, the “animal spirit” is directed to the brain, reflected from it and along the corresponding nerves (tubes) is directed to the muscles, inflating them. Here you can easily see a simple analogy with hydraulic machines, which in the time of R. Descartes were the pinnacle of engineering achievement. Drawing an analogy between the action of artificial mechanisms and the activity of the brain is a favorite technique when describing brain functions. For example, our great compatriot I.P. Pavlov compared the function of the cerebral cortex with a telephone exchange where a young lady telephone operator connects subscribers to each other. Nowadays, the brain and its activities are most often compared to a powerful computer. However, any analogy is very conditional. There is no doubt that the brain does perform a huge amount of calculations, but the principle of its operation is different from the principles of the computer. But let’s return to the question: why does a psychologist need to know the physiology of the brain?

Let us recall the idea of a reflex, expressed back in the 18th century by R. Descartes. Actually, the kernel of this idea was the recognition that the reactions of living organisms are caused by external stimuli due to the activity of the brain, and not “by the will of God.” In Russia, this idea was enthusiastically received by the scientific and literary community. The pinnacle of this was the publication of the famous work of Ivan Mikhailovich Sechenov “Reflexes of the Brain” (1863), which left a deep mark on world culture. Evidence is provided by the fact that in 1965, the centenary of the publication of this book, an international conference was held in Moscow under the patronage of UNESCO, which was attended by many of the world's leading neurophysiologists. I.M. Sechenov was the first to fully and convincingly prove that human mental activity should become an object of study by physiologists.

I. P. Pavlov developed this idea in the form of “the doctrine of the physiology of conditioned reflexes.”

He is credited with creating a method for experimental research on the “highest floor” of the brain cortex - the cerebral hemispheres. This method is called the “conditioned reflex method.” He established the fundamental pattern of presenting to an animal (I.P. Pavlov conducted research on dogs, but this is also true for humans) of two stimuli - first conditional (for example, the sound of a buzzer), and then unconditional (for example, feeding the dog pieces of meat). After a certain number of combinations, this leads to the fact that when only the sound of a buzzer (conditioned signal) is applied, the dog develops a food reaction (saliva is released, the dog licks, whines, looks towards the bowl), i.e. a conditioned food reflex has formed (Fig. 3). Actually, this training technique has been known for a long time, but I.P. Pavlov made it a powerful tool for scientific research of brain functions.

Physiological studies combined with the study of the anatomy and morphology of the brain have led to an unequivocal conclusion - it is the brain that is the instrument of our consciousness, thinking, perception, memory and other mental functions.

The main difficulty of the study is that mental functions are extremely complex. Psychologists study these functions using their own methods (for example, using special tests they study a person’s emotional stability, level of mental development and other mental properties). Characteristics of the psyche are studied by a psychologist without being “linked” to brain structures, i.e. the psychologist is interested in questions organizations mental function itself, but not that how they work individual parts of the brain when performing this function. Only relatively recently, several decades ago, technical capabilities appeared to study using physiological methods (registration of bioelectrical activity of the brain, study of the distribution of blood flow, etc., see below for more details) of some characteristics of mental functions - perception, attention, memory, consciousness, etc. The combination of new approaches to the study of the human brain, the sphere of scientific interests of physiologists in the field of psychology, led to the emergence of a new science in the border area of these sciences - psychophysiology. This led to the interpenetration of two areas of knowledge - psychology and physiology. Therefore, a physiologist who studies the functions of the human brain needs knowledge of psychology and the application of this knowledge in his practical work. But a psychologist cannot do without recording and studying objective brain processes using electroencephalograms, evoked potentials, tomographic studies, etc.

Methods of neurophysiological research. Electrical activity of the brain.

In physiology they distinguish two main methods: observation and experiment.

Observation method consists in passively recording the progress of a particular process or phenomenon.

Experiment– this is the study of any function through active influence. There are two types of experiment; acute and chronic. In acute In the experiment, the researcher cuts out the structures of interest to him (PR - cerebellum). Such an experiment entails the death of experimental animals. Chronic experiment studies functions in close connection with other functions of the body - the experimental animal does not die.

In clinical practice they use

In physiology, VNI was developed by Pavlov conditioned reflex method. Using this method, he studied the functions of the cerebral cortex, subcortical formations, the phenomena of concentration and irradiation, and the analytical and synthetic activity of the brain.

In modern conditions, electrophysiological methods that allow recording biopotentials (electrocardiography, electroencephalography, electromyography) are used to study physiological processes. Using computed tomography, it is possible to establish morphofunctional changes in the brain without resorting to surgery.

Methods for studying the brain.

1) morphological methods - study of the fine structure brain (detection of the finest elements of nerve cells) using light and electron microscopy, radiochemistry.

2) biochemical methods – study of metabolic processes in the brain of a healthy and sick person, as well as in various functional states, forms of activity, etc. Several areas of neurochemistry will be highlighted - the chemistry of peptides, mediators, modulators, amino acids, etc.

3) physiological methods – experimental methods aimed at studying the functions of various parts of the brain.

· Brain destruction method. Initially it was used to simulate situations in which people with local brain lesions find themselves. In clinical practice use method of destruction of central nervous system structures for treatment purposes (for example, drug addiction treatment). The study and destruction of brain structures for therapeutic purposes has found application in the clinic of Academician Bekhtereva for the treatment of various forms of central nervous system diseases.

· Method of electrical stimulation of the brain– was introduced into experimental physiology from the mid-19th century. In modern science A stereotactic technique is used, which allows the electrode to be inserted into any very local area of the brain. This technique is also used to treat a number of neurological and mental diseases.

· Chemostimulation method, thermo- and chemical destruction, ultrasonic destruction - allows you to achieve even greater locality.

· Method for recording electrical processes of the brain- used since the second half of the 20th century. Electroencephalography method is a method of recording the electrical activity of the brain, mainly cortical neurons. A curve representing electrical activity is called electroencephalogram. An electroecephalograph is used for recording. In general, EEG allows us to determine the nature of the brain state (PR - epilepsy).

· Method for studying cerebral blood flow - method reencephalography(REG). REG recording is carried out using a rheograph connected to an electroencephalograph. REG is a curve made up of ascending and descending paths. It has peaks and teeth on the descent of the curve. REG is a harmless method for diagnosing cerebral disorders. Cerebral blood flow in the carotid and vertebral arteries is studied.

· Tomographic methods(computed tomography of the head). The essence of tomographic studies is to obtain a slice of the brain artificially. To construct a slice, either X-rays of the brain are used, or radiation from the brain emanating from isotopes previously introduced into the brain. This method is widely used for diagnosing diseases of the central nervous system (the localization of tumors, hemorrhages, etc. can be identified).

Electrical activity of the brain.

Fluctuations in the electrical potentials of the cortex were first recorded by V.V. Pravdich-Nilinsky in 1913. Fluctuations in cortical potentials are recorded using an electroencephalograph. The EEG distinguishes between waves of different frequencies and amplitudes. According to the frequency of oscillations in 1 s. There are alpha rhythm, beta rhythm, theta rhythm, delta rhythm.

Characteristics of brain biorhythms:

Diagnostic value of the electroencephalogram: in a healthy person, alpha and beta waves should be recorded in a state of wakefulness; otherwise, it is a sign of pathology in the brain (hemorrhages, tumors).

Neurophysiology is a branch of animal and human physiology that studies the functions of the nervous system and its main structural units - neurons. It is closely related to neurobiology, psychology, neurology, clinical neurophysiology, electrophysiology, ethology, neuroanatomy and other sciences that study the brain.

Methods for studying the central nervous system:

Experimental:

Cut-off method

Cold shutdown methods

Molecular Biology Methods

Stereotactic method

Clinical:

Electroencephalography

Method for recording cell impulse activity

Tomographic methods

Rheoencephalography

Echoencephalography

Experimental methods:

1. Cut-off method different parts of the central nervous system is produced in different ways. Using this method, you can observe changes in conditioned reflex behavior.

2. Cold shutdown methods brain structures make it possible to visualize the spatio-temporal mosaic of electrical processes in the brain during the formation of a conditioned reflex in different functional states.

3. Molecular biology methods are aimed at studying the role of DNA, RNA molecules and other biologically active substances in the formation of a conditioned reflex.

4. Stereotactic method consists in the fact that an electrode is introduced into the animal’s subcortical structures, with the help of which one can irritate, destroy, or inject chemicals. Thus, the animal is prepared for a chronic experiment. After the animal recovers, the conditioned reflex method is used.

Clinical methods:

Electroencephalography- registration of rhythmic changes in the potentials of certain areas of the cerebral cortex between two active electrodes (bipolar method) or an active electrode in a certain zone of the cortex and a passive electrode superimposed on an area remote from the brain. Electroencephalogram is a recording curve of the total potential of the constantly changing bioelectrical activity of a significant group of nerve cells.

Method for recording impulsive cell activity- to record neural impulse activity of the human brain, microelectrodes with tip diameters of 0.5-10 microns are used. The electrodes are inserted into the brain using special micromanipulators, which allow the electrode to be precisely positioned to the desired location.

Tomography – is based on obtaining images of brain slices using special techniques. The idea of this method was proposed by J. Rawdon in 1927, who showed that the structure of an object can be restored from the totality of its projections, and the object itself can be described by many of its projections. ( Computed tomography, Positron emission tomography)

Rheoencephalography is a method for studying the blood circulation of the human brain, based on recording changes in the resistance of brain tissue to high-frequency alternating current depending on the blood supply and allows one to indirectly judge the amount of total blood supply to the brain, the tone, elasticity of its vessels and the state of venous outflow.

Echoencephalography- is based on the property of ultrasound - it is reflected differently from brain structures, cerebrospinal fluid, skull bones, and pathological formations. In addition to determining the size of the localization of certain brain formations, this method allows you to estimate the speed and direction of blood flow.

Subject, content, significance of neurophysiology. Formation and development of science.

Design of drawings

Today, higher and secondary specialized educational institutions pay great attention to the use of computer technology in teaching students. During their studies, students master the most promising design technologies and acquire skills in working with computer graphics systems.

When preparing drawing materials, students can use any available drawing editors, subject to compliance with GOST ESKD. Here is a description of “COMPASS”.

The KOMPAS program is a COMPLEX of Automated Systems, specially created to solve a wide range of design and construction problems. The KOMPAS-GRAFIC drawing and graphic editor built into the system was initially focused on the quick and convenient execution of drawings of any complexity in full compliance with GOST ESKD.

The drawing and graphic editor KOMPAS-GRAFIC is an excellent tool for completing design documentation. Thanks to a simple interface that complies with the Window standard, the editor provides quick learning with the system at a whole new level. System control is provided using a drop-down text menu, separate toolbars and a context menu. The user can create his own toolbars, as well as connect libraries in one of the types: window, dialog, menu or panel.

During the design process in the editor, you can work with all types of graphic primitives (points, lines, circles, arcs of circles, ellipses, etc.), make any auxiliary constructions, correctly dimension with tolerances, use an auxiliary grid, local coordinate systems, local and global bindings, edit a drawing, take measurements and calculate the mass and dimensional characteristics of bodies.

Confident work in the editor will speed up the completion of coursework and diploma projects

Students get the opportunity to use this tool in their future professional activities.

Students must:

Know the rules for constructing images, the methodology of working in the Compass system;

Be able to create design documentation (graphic and textual) in the Compass system;

Have experience in creating workshop (site) layout drawings, as well as preparing design documentation in the Compass system in accordance with ESKD standards.

Examples of drawings are given in Appendix B.