The contribution to science of the Russian and Soviet scientist Ivan Petrovich Pavlov cannot be overestimated. Physiologist, vivisector, Nobel laureate, researcher - you can talk about him for a long time. But now we will talk about the famous theory of Pavlov - about its main provisions, key principles, features and significance.
About the study
The object of attention of the Soviet vivisector was the "real physiology" of the brain of dogs. Studying it, Pavlov was able to accurately define the concept of higher nervous activity (HNA).
What conclusions did the scientist make? He assured that the activity of the cerebral hemispheres with the subcortex, which ensures the complex interaction of the organism with the outside world, should be called the highest. And it is fair to oppose to it the activity carried out by further parts of the spinal cord and brain. Since they "manage" only the integration and correlation of parts of the body. This, in turn, is called the lower nervous activity.
Considering Pavlov's theory, we must make a reservation that it concerns the physiology of higher nervous activity, andnot mental functions. It is wrong to identify these concepts, as the mechanistic materialists did (because of which, by the way, psychology was no longer considered an independent science).
I. P. Pavlov studied the GNI of dogs, not people, and he himself focused on the fact that it is unacceptable to identify the activity of the nervous system of an animal with the human psyche.
Basics
Taking into account all of the above, we can move on to the main topic. Here are some of the concepts identified in Pavlov's theory:
- Higher nervous activity. That which provides the animal with behavior in the outside world that corresponds to the conditions of life.
- Lower nervous activity. Responsible for the reflex independent regulation of the work carried out by internal organs.
Based on these simple definitions, one can understand that Pavlov contrasted these two types of activity. But even despite this, a tendency has spread, on the contrary, to identify them.
Be that as it may, in the unity of both nervous activities, which can be traced in the combination of vegetative reflexes with motor reflexes, the leading role is assigned to the latter. Why? Because it is motor reflexes that determine the self-regulation of the work of the digestive, cardiovascular, and other systems of internal organs.
It's important to explain something here. The fact is that the "turning on" of some reflexes is determined by others. What? Motor-visceral and cerebral reflexes control motor-visceral and cerebral reflexes.
What kind ofdraw a conclusion? The author of the theory - Pavlov - formulated it as follows: “The GNI of a living organism is formed by conditioned and unconditioned reflexes. And the education of one without the other is impossible.”
On the importance of the cerebral cortex
Continuing to study the features of IP Pavlov's theory, the following nuance should be noted: the general behavior of people and higher animals is controlled by the highest department of the central nervous system. That is, the cerebral hemispheres with the nearest subcortex. What, proceeding from this position, is the higher nervous activity? It can be argued that this is a combined function of the subcortical centers and the cerebral hemispheres.
Also, Pavlov's theory does not exclude the possibility that, under certain circumstances, conditioned reflexes can form in other parts of the brain, outside the cerebral hemispheres.
If we talk about dogs, then we need to highlight one interesting point. The fact is that adult dogs without a cerebral cortex completely lose all the conditioned reflexes acquired by them during their life. They stop responding to the owner, to the nickname, etc. And this leads to a breakdown in communication with the outside world. However, after removal of the cerebral cortex, dogs may develop conditioned motor reflexes.
By the way, S. S. Poltyrev, G. P. Zeleny, and N. N. Dzidzishvili devoted their works to this topic. In general, many scientists have been able to establish that in dogs, cats and rabbits, the removal of the cerebral cortex entails the formation of conditioned vegetative reflexes. This is a proven fact.
Effect of removing parts of the barkbrain on reflexes
This is a very important topic, and it needs to be given attention when talking about the principles of Pavlov's reflex theory. Removal of certain parts of the cerebral cortex is reflected in the reflexes. And here's how:
- Removal of the neocortex. After that, conditioned defensive and food reflexes are developed in dogs and cats. But if the archio- and paleocortex are additionally removed, then the probability of their formation is reduced to a minimum. Reflexes are formed, but rarely, and are very different from the true ones.
- Removal of the new cerebral cortex. After that, conditioned reflexes are closed in cats, localized in the hippocampus and cingulate gyrus. In order for them to form, an old and ancient bark is needed - they form an emotional background. And it is a necessary condition for the development of reflexes.
- Hypocampus removal. This operation has no effect on the rate of formation of food reflexes, however, it makes it difficult to strengthen them. This happens due to a sharp increase in the orientation reaction, the cause of which is the prolapse of the hippocampus, which inhibits the reticular formation. In general, due to its removal, internal inhibition of reflexes is disturbed. The formation of short-term memory is even more complicated. Also, after the elimination of the hippocampus, defensive reflexes are not formed.
- Removal of the almond-shaped nuclei. As a result of this operation, the animal's normal behavior is disturbed, which corresponds to a particular situation. This operation does not affect food reflexes in any way, but defensive reflexes disappear, after which they are restored withhard work.
- Removal from the cingulate anterior gyrus of the patella. It has been proved that as a result of this, disinhibition of food inhibitory motor reflexes occurs. But the removal of the back section does not affect this process in any way. Accordingly, the front part is one of the most important areas of inhibition of certain affective reactions.
- Bilateral removal of premotor areas. Interference of this kind entails the formation of motor conditioned reflexes.
- Damage to the reticular formation localized in the midbrain. This operation is fraught with the disappearance of the salivary reflex.
- Removal of the frontal lobes (more precisely, their anterior parts). This entails a violation of the inhibition of motor and salivary reflexes.
Considering the features, provisions and principles of Pavlov's theory, it is worth noting that the following has also been proven: the formation of the notorious reflexes is simplified if the sympathetic nuclei located in the hypothalamic region are excited. But they will disappear if they are damaged.
However, of course, these are just some of the features that can be distinguished from Pavlov's theory of higher nervous activity. In our time, such experiments continue, and now they use special microelectrodes that irritate certain parts of the brain, which helps to follow the process of the formation / disappearance of reflexes.
Conclusions and evidence
The key principles of Pavlov's reflex theory were discussed above. If you study all of itposition, then we can draw a logical, reasonable conclusion: the removal of the new cerebral cortex entails the formation of conditioned reflexes in the old and ancient cortex (that is, in the subcortical centers).
Proceeding from this, another statement follows. It says: the opinion that the notorious conditioned reflexes are formed in animals exclusively in the cerebral cortex is incorrect. Why? Because it contradicts reality - after all, conditioned reflexes are also formed in those creatures in which the cerebral cortex is absent. Fish and insects are prime examples.
It was on the basis of these facts that the well-known scientist argued that GNI is inherent in all, without exception, all animals with a nervous system. And it is carried out by the higher department of the nervous system.
Meaning of the theory
It also needs to be told about. Thanks to Pavlov's reflex theory, it became possible to study the activity of the brain not only in animals, but also in humans (of course, in natural conditions). The basic laws of GNI were revealed largely due to the work done by the scientist. Here is what contributed to this:
- Knowledge of the basic laws of the central nervous system.
- Accurate accounting of the quality of stimuli, as well as how long the effect they have on receptors, and what their intensity.
- Knowing the time of formation of the reflex, as well as its magnitude and nature.
Pavlov's theory of conditioned reflexes is the basis for the prehistory of consciousness as the highest form of the psyche that is inherent in man.
Needto say that the method of the scientist, as well as his works, make it possible to study the qualitative features of the activity that occurs in the human brain. It is the theory of activity formed by Pavlov that constitutes the natural-scientific basis for the dialectical-materialist worldview. Why? Because it is on the works of the scientist that the philosophy of dialectical materialism relies in the fight against ideas of an idealistic and metaphysical nature.
It should also be noted that after the spread of Pavlov's theory, a negative attitude towards psychology strengthened in society. Because some researchers tried to “dissolve” its subject in the physiology of GNA in order to present it as the only opportunity for studying the psyche. The identification of this concept with higher nervous activity turned out to be fraught not only with the biologization of people. It also led to the fact that people began to deny the socio-historical essence of the human psyche.
Theory of Sechenov and Pavlov
It is thanks to the tandem of these two greatest scientists that a new stage has been outlined in the history of the study of brain physiology. And by the way, it was Ivan Mikhailovich Sechenov who was the first to formulate the reflex theory.
I. P. Pavlov and his colleague formed a very fruitful tandem. Their common work is a kind of materialistic determinism in the field of studying the functions of the central nervous system. The theory they created became the basis for the subsequent development of the psychology and physiology of GNA.
You should pay some attention to studying it. Keythe provisions of the reflex theory of I. P. Pavlov and I. M. Sechenov can be distinguished in such a small list:
- Determinism. In other words, causality. This principle is manifested in the following: each reflex reaction is conditioned. There can be no action without a reason. Any act of nervous activity is a reaction to an impact coming from the internal or external environment.
- Structural. This principle says: all reflex reactions occur with the help of certain brain structures. There are no processes that do not have a material basis. Any act of nervous activity is necessarily timed to a specific structure.
- Analysis and synthesis. These concepts also take place in Pavlov's theory. In short, the nervous system is always analyzing stimuli that affect the body. And then synthesizes a response. These two processes are going on all the time. Their result is the extraction by the body from the environment of the information that it needs, and its further processing, followed by fixation in memory. The last stage is the formation of a response that always matches the needs and circumstances.
Studying the reflex theory of Pavlov and Sechenov, I would like to pay attention to the concept of nervism. This is the name of the concept, which recognizes the following fact: the nervous system plays a leading role in the regulation of the functions of all tissues and organs.
Psychic aspect
He also has a place. The importance of the mental aspect has always been emphasized by I. M. Sechenov. first parthe characterized the reflex act as a signal.
What does this mean? Sensory signals seem to “notify” the nervous system about what is happening in the external environment. And Pavlov, who adhered to the physiological aspect, recognized the need to supplement the theory with a provision on the signaling system. This is expedient in relation to the person.
Also, Pavlov confirmed the need to start studying the signaling system associated with the role of speech in the human psyche. This is already directly related to the topic of consciousness - different, but still relevant to the theory under consideration. After all, it was the development of the human brain that became its first prerequisite. Yes, and the main law of the biological improvement of organisms, which determines the formation of the psyche, is the position that speaks of the unity of their structure and functions.
Fundamental properties of nervous processes
They must be listed before proceeding to consider Pavlov's theory of temperament. The scientist devoted a lot of time to studying the development of conditioned reflexes, and he managed to establish that there is a certain individuality in this process. And its basis is certain properties, namely:
- Power of arousal. In other words, performance, endurance of the nerve cell. It manifests itself in the maintenance of strong excitation by the nervous system, which does not end with a transition to a state of inhibition. By the way, both of these processes are independent properties of the NS.
- Braking force. It shows the abilitynervous system to extinction and differentiation.
- Poise. This property determines the balance between the processes of inhibition and excitation. A person, for example, can be called physiologically unbalanced if the strength of one of these two processes is greater than the other.
- Mobility. It determines how quickly one nervous process passes into another. Mobility is the ability to change behavior depending on external conditions. The opposite process is inertia. A person can be called inert if it takes him a long time to move from a passive state to an active one.
Typology of temperaments
Having studied the theory of Pavlov's reflexes, we can move on to this topic. Properties of nervous processes, as determined by the scientist, form combinations that determine the type of GNI or the entire system itself. What is it made up of? From the set of key properties of the nervous system listed above.
What is Pavlov's theory of temperament? The scientist proved that there are four types of the nervous system. And they are very similar to the types of temperament according to Hippocrates.
Power differences define weak and powerful types. They, in turn, can be of two types:
- Balanced. Excitation and inhibition are in balance. But nevertheless, they are prone to inertia or to mobility.
- Unbalanced. In this case, excitation strongly predominates over inhibition.
Types of the nervous system, according to Pavlov, also correspond to the types of temperament in terms of characteristics (and not just in quantity). This iscan be traced:
- Mobile type. Distinguished by poise and strength - sanguine.
- Inert type, but distinguished by strength and poise - phlegmatic.
- Strong and unbalanced, with a predominance of excitement - choleric.
- Weak type - melancholic.
The type of nervous system (just like temperament) is an innate property. Almost impossible to change. Moreover, the type of nervous system is considered the physiological basis of temperament. And he, in turn, is a mental manifestation of the NS type.
Further experiments
In the 1950s, a large-scale study of the behavior of adults was organized. At first it was led by V. M. Teplov, but then it came under the leadership of V. D. Nebylitsyn. As a result of this study, the main provisions of Pavlov's theory were supplemented with new ones.
Firstly, it was possible to develop methods for studying the properties inherent in the human nervous system. Secondly, it turned out to highlight and describe two more qualities. Among them:
- Lability. Manifested in the speed of occurrence, and then the cessation of nervous processes.
- Dynamism. It affects the ease and speed of the formation of inhibitory and positive conditioned reflexes.
Today, science has accumulated a lot of different facts regarding the properties of the nervous system. And the more they become (progress does not stand still), the less importance is attached to the types of NS. Certain properties of the nervous system are recognized as more significant, whichare indeed fundamental. Many scientists relegate the problem of dividing NS into types into the background.
However, since they are just formed from a combination of the listed properties, only their detailed study can provide the most complete understanding of the typology.
