Differences between conditioned reflexes and unconditioned ones. Without conditioned reflexes- innate reactions of the body, they were formed and consolidated in the process of evolution and are inherited. Conditioned reflexes arise, become consolidated, and fade away throughout life and are individual. Unconditioned reflexes are specific, i.e. they are found in all individuals of a given species. Conditioned reflexes may be developed in some individuals of a given species, but absent in others; they are individual. Unconditioned reflexes do not require special conditions For their occurrence, they necessarily arise if adequate stimuli act on certain receptors. Conditioned reflexes require special conditions for their formation; they can be formed in response to any stimuli (of optimal strength and duration) from any receptive field. Unconditioned reflexes are relatively constant, persistent, unchanging and persist throughout life. Conditioned reflexes are changeable and more mobile.
Unconditioned reflexes can occur at the level of the spinal cord and brain stem. Conditioned reflexes can be formed in response to any signals perceived by the body and are primarily a function of the cerebral cortex, realized with the participation of subcortical structures.
Unconditioned reflexes can ensure the existence of an organism only at the very early stage of life. The body's adaptation to constantly changing environmental conditions is ensured by conditioned reflexes developed throughout life. Conditioned reflexes are changeable. In the process of life, some conditioned reflexes, losing their meaning, fade away, while others are developed.
Biological significance of conditioned reflexes. The body is born with a certain fund unconditioned reflexes. They provide him with the maintenance of vital functions in relatively constant conditions of existence. These include unconditioned reflexes: food (chewing, sucking, swallowing, secretion of saliva, gastric juice, etc.), defensive (pulling a hand away from a hot object, coughing, sneezing, blinking when a stream of air enters the eye, etc.), sexual reflexes (reflexes associated with sexual intercourse, feeding and caring for offspring), thermoregulatory, respiratory, cardiac, vascular reflexes that maintain the constancy of the internal environment of the body (homeostasis), etc.
Conditioned reflexes provide a more perfect adaptation of the body to changing living conditions. They help to find food by smell, timely escape from danger, and orientation in time and space. Conditioned reflex separation of saliva, gastric, pancreatic juices in appearance, smell, meal time creates Better conditions to digest food before it enters the body. Enhancing gas exchange and increasing pulmonary ventilation before starting work, only when seeing the environment in which the work is being done, contributes to greater endurance and better performance of the body during muscular activity.
When a conditioned signal is applied, the cerebral cortex provides the body with preliminary preparation of a response to those stimuli external environment, which will have an impact in the future. Therefore, the activity of the cerebral cortex is signaling.
Conditions for the formation of a conditioned reflex. Conditioned reflexes are developed on the basis of unconditioned ones. The conditioned reflex was so named by I.P. Pavlov because certain conditions are needed for its formation. First of all, you need a conditioned stimulus, or signal. A conditioned stimulus can be any stimulus from the external environment or a certain change in the internal state of the body. In the laboratory of I.P. Pavlov, the flashing of an electric light bulb, the bell, the gurgling of water, skin irritation, taste, olfactory stimuli, the clinking of dishes, the sight of a burning candle, etc. were used as conditioned stimuli. Conditioned reflexes are temporarily developed in a person by observing a work regime, eating at the same time, consistent with bedtime.
A conditioned reflex can be developed by combining an indifferent stimulus with a previously developed conditioned reflex. In this way, conditioned reflexes of the second order are formed, then the indifferent stimulus must be reinforced with a conditioned stimulus of the first order. It was possible to form conditioned reflexes of the third and fourth orders in the experiment. These reflexes are usually unstable. Children managed to develop sixth-order reflexes.
The possibility of developing conditioned reflexes is hampered or completely eliminated by strong extraneous stimuli, illness, etc.
In order to develop a conditioned reflex, the conditioned stimulus must be reinforced with an unconditioned stimulus, that is, one that evokes an unconditioned reflex. The clinking of knives in the dining room will cause a person to salivate only if this clinking has been reinforced with food one or more times. The clinking of knives and forks in our case is a conditioned stimulus, and the unconditioned stimulus that causes the salivary unconditioned reflex is food. The sight of a burning candle can become a signal for a child to withdraw his hand only if at least once the sight of a candle coincides with pain from a burn. When a conditioned reflex is formed, the conditioned stimulus must precede the action of the unconditioned stimulus (usually by 1-5 s).
The mechanism of formation of a conditioned reflex. According to the ideas of I.P. Pavlov, the formation of a conditioned reflex is associated with the establishment of a temporary connection between two groups of cortical cells: between those who perceive conditioned and those who perceive unconditional stimulation. This connection becomes stronger the more often both areas of the cortex are simultaneously excited. After several combinations, the connection turns out to be so strong that under the influence of only one conditioned stimulus, excitation also occurs in the second focus (Fig. 15).
Initially, an indifferent stimulus, if it is new and unexpected, causes a general generalized reaction of the body - an orienting reflex, which I. P. Pavlov called the exploratory or “what is it?” reflex. Any stimulus, if used for the first time, causes a motor reaction (general shudder, turning the eyes and ears towards the stimulus), increased breathing, heartbeat, generalized changes in the electrical activity of the brain - the alpha rhythm is replaced by rapid oscillations (beta rhythm). These reactions reflect generalized generalized arousal. When a stimulus is repeated, if it does not become a signal for a specific activity, the orienting reflex fades away. For example, if a dog hears a bell for the first time, it will give a general approximate reaction to it, but will not produce saliva. Let's back it up now ringing bell food. In this case, two foci of excitation will appear in the cerebral cortex - one in the auditory zone, and the other in the food center (these are areas of the cortex that are excited under the influence of the smell and taste of food). After several reinforcements of the bell with food, a temporary connection will arise (close) in the cerebral cortex between the two foci of excitation.
In the course of further research, facts were obtained indicating that the closure of the temporary connection occurs not only along horizontal fibers (bark - bark). With cuts gray matter separated in dogs different areas cortex, however, this did not prevent the formation of temporary connections between the cells of these areas. This gave reason to believe that the cortex-subcortex-cortex pathways also play an important role in establishing temporary connections. In this case, centripetal impulses from the conditioned stimulus through the thalamus and nonspecific system (hippocampus, reticular formation) enter the corresponding zone of the cortex. Here they are processed and along descending pathways reach the subcortical formations, from where the impulses come again to the cortex, but already in the zone of representation of the unconditioned reflex.
What happens in the neurons involved in the formation of a temporary connection? On this occasion there is various points vision. One of them assigns the main role to morphological changes in the endings of nerve processes.
Another point of view about the mechanism of the conditioned reflex is based on the principle of dominance by A. A. Ukhtomsky. In the nervous system at each moment of time there are dominant foci of excitation - dominant foci. The dominant focus has the property of attracting to itself the excitation entering other nerve centers, and thereby intensifying. For example, during hunger, a persistent focus with increased excitability appears in the corresponding parts of the central nervous system - a food dominant. If you let a hungry puppy lap milk and at the same time begin to irritate the paw with an electric current, then the puppy does not withdraw its paw, but begins to lap with even greater intensity. In a well-fed puppy, irritation of the paw with an electric current causes a reaction of its withdrawal.
It is believed that during the formation of a conditioned reflex, the focus of persistent excitation that arose in the center of the unconditioned reflex “attracts” to itself the excitation that arose in the center of the conditioned stimulus. As these two excitations combine, a temporary connection is formed.
Many researchers believe that the leading role in fixing the temporary connection belongs to changes in protein synthesis; Specific protein substances associated with imprinting a temporary connection have been described. The formation of a temporary connection is associated with the mechanisms of storing traces of excitation. However, memory mechanisms cannot be reduced to “belt connection” mechanisms.
There is evidence of the possibility of storing traces at the level of single neurons. Cases of imprinting from a single action of an external stimulus are well known. This gives grounds to believe that the closure of a temporary connection is one of the mechanisms of memory.
Inhibition of conditioned reflexes. Conditioned reflexes are plastic. They can persist for a long time, or they can be inhibited. Two types of inhibition of conditioned reflexes have been described - internal and external.
Unconditional, or external, inhibition. This type of inhibition occurs in cases where in the cerebral cortex, during the implementation of a conditioned reflex, a new, sufficiently strong focus of excitation appears, not associated with this conditioned reflex. If a dog has developed a conditioned salivary reflex to the sound of a bell, then turning on a bright light at the sound of a bell in this dog inhibits the previously developed salivation reflex. This inhibition is based on the phenomenon of negative induction: a new strong focus of excitation in the cortex from extraneous stimulation causes a decrease in excitability in the areas of the cerebral cortex associated with the implementation of the conditioned reflex, and, as a consequence of this phenomenon, inhibition of the conditioned reflex occurs. Sometimes this inhibition of conditioned reflexes is called inductive inhibition.
Inductive inhibition does not require development (that is why it is classified as unconditioned inhibition) and develops immediately as soon as an external stimulus, foreign to the given conditioned reflex, acts.
External braking also includes transcendental braking. It manifests itself when the strength or time of action of the conditioned stimulus increases excessively. In this case, the conditioned reflex weakens or completely disappears. This inhibition has a protective value, as it protects nerve cells from stimuli of too great strength or duration that could disrupt their activity.
Conditioned, or internal, inhibition. Internal inhibition, in contrast to external inhibition, develops within the arc of the conditioned reflex, i.e., in those nervous structures that are involved in the implementation of this reflex.
If external inhibition occurs immediately as soon as the inhibitory agent has acted, then internal inhibition must be developed; it occurs under certain conditions, and this sometimes takes a long time.
One type of internal inhibition is extinction. It develops if the conditioned reflex is not reinforced by an unconditioned stimulus many times.
Some time after extinction, the conditioned reflex can be restored. This will happen if we again reinforce the action of the conditioned stimulus with the unconditioned one.
Fragile conditioned reflexes are restored with difficulty. Extinction can explain the temporary loss of labor skills and the ability to play musical instruments.
In children, decline occurs much more slowly than in adults. This is why it is difficult to wean children from bad habits. Extinction is the basis of forgetting.
The extinction of conditioned reflexes has important biological significance. Thanks to it, the body stops responding to signals that have lost their meaning. How many unnecessary, superfluous movements would a person make during writing, labor operations, and sports exercises without extinctive inhibition!
The delay of conditioned reflexes also refers to internal inhibition. It develops if the reinforcement of a conditioned stimulus by an unconditioned stimulus is delayed. Usually, when developing a conditioned reflex, a conditioned stimulus-signal (for example, a bell) is turned on, and after 1-5 s food is given (unconditioned reinforcement). When the reflex is developed, immediately after the bell is turned on, without giving food, saliva begins to flow. Now let’s do this: turn on the bell, and gradually delay the food reinforcement until 2-3 minutes after the bell starts sounding. After several (sometimes very multiple) combinations of a sounding bell with delayed reinforcement with food, a delay develops: the bell turns on, and saliva will no longer flow immediately, but 2-3 minutes after the bell is turned on. Due to the non-reinforcement of the conditioned stimulus (bell) for 2-3 minutes by the unconditioned stimulus (food), the conditioned stimulus acquires an inhibitory value during the period of non-reinforcement.
The delay creates conditions for better orientation of the animal in the surrounding world. The wolf does not immediately rush at the hare when it sees it at a considerable distance. He waits for the hare to approach. From the moment the wolf saw the hare until the time the hare approached the wolf, a process of internal inhibition takes place in the wolf’s cerebral cortex: motor and food conditioned reflexes are inhibited. If this did not happen, the wolf would often be left without prey, breaking into pursuit as soon as he sees the hare. The resulting delay provides the wolf with prey.
Delay in children is developed with great difficulty under the influence of upbringing and training. Remember how a first-grader impatiently reaches out his hand, waving it, getting up from his desk so that the teacher notices him. And only by high school age (and even then not always) do we notice endurance, the ability to restrain our desires, and willpower.
Similar sound, olfactory and other stimuli can signal completely different events. Only an accurate analysis of these similar stimuli ensures biologically appropriate reactions of the animal. Analysis of stimuli consists of distinguishing, separating different signals, differentiating similar interactions on the body. In the laboratory of I.P. Pavlov, for example, it was possible to develop the following differentiation: 100 metronome beats per minute were reinforced with food, and 96 beats were not reinforced. After several repetitions, the dog distinguished 100 metronome beats from 96: at 100 beats she salivated, at 96 beats the saliva did not separate. Discrimination, or differentiation, of similar conditioned stimuli is developed by reinforcing some and non-reinforcing other stimuli. The inhibition that develops suppresses the reflex reaction to non-reinforced stimuli. Differentiation is one of the types of conditioned (internal) inhibition.
Thanks to differential inhibition, it is possible to identify signal-significant signs of a stimulus from many sounds, objects, faces, etc. around us. Differentiation is developed in children from the first months of life.
Dynamic stereotype. External world acts on the body not by single stimuli, but usually by a system of simultaneous and sequential stimuli. If this system is often repeated in this order, then this leads to the formation of a dynamic stereotype.
A dynamic stereotype is a sequential chain of conditioned reflex acts, carried out in a strictly defined, time-fixed order and resulting from a complex systemic reaction of the body to a complex of conditioned stimuli. Thanks to the formation of chain conditioned reflexes, each previous activity of the body becomes a conditioned stimulus - a signal for the next one. Thus, by previous activity the body is prepared for the subsequent one. A manifestation of a dynamic stereotype is a conditioned reflex for time, which contributes to the optimal functioning of the body with the correct daily routine. For example, eating at certain hours ensures good appetite and normal digestion; Consistency in keeping a bedtime helps children and adolescents fall asleep quickly and thus sleep longer; Carrying out educational work and work activities always at the same hours leads to faster processing of the body and better absorption knowledge, skills, abilities.
A stereotype is difficult to develop, but if it is developed, then maintaining it does not require significant strain on cortical activity, and many actions become automatic. ;d A dynamic stereotype is the basis for the formation of habits in a person, the formation of a certain sequence in labor operations, and the acquisition of skills.
Walking, running, jumping, skiing, playing the piano, using a spoon, fork, knife when eating, writing - all these are skills that are based on the formation of dynamic stereotypes in the cerebral cortex.
The formation of a dynamic stereotype underlies the daily routine of every person. Stereotypes persist long years and form the basis of human behavior. Stereotypes that arise in early childhood are very difficult to change. Let us remember how difficult it is to “retrain” a child if he has learned to hold a pen incorrectly when writing, sit incorrectly at the table, etc. The difficulty of remaking stereotypes forces Special attention on the correct methods of raising and teaching children from the first years of life.
A dynamic stereotype is one of the manifestations of the systemic organization of higher cortical functions aimed at ensuring stable reactions of the body.
To pull your hand away from a hot kettle, to close your eyes when there is a flash of light... We perform such actions automatically, without having time to think about what exactly we are doing and why. These are unconditioned human reflexes - innate reactions characteristic of all people without exception.
Discovery history, types, differences
Before considering unconditioned reflexes in detail, we will have to make small excursion into biology and talk about reflex processes in general.
So what is a reflex? In psychology, this is the name given to the body’s response to changes in external or internal environment, which is carried out using the central nervous system. Thanks to this ability, the body quickly adapts to changes in the surrounding world or in its internal state. For its implementation, a reflex arc is necessary, that is, the path along which the signal of irritation passes from the receptor to the corresponding organ.
Reflex reactions were first described by Rene Descartes in the 17th century. But the French scientist believed that this was not psychological phenomenon. He considered reflexes as part of the objective natural science knowledge, psychology at that time was considered not to be a science, because it dealt only with subjective reality and was not subject to objective experiment.
And if the sense organs do not experience irritation, and sensitivity is lost, mental life freezes. Let's remember famous expression: “get tired to the point of losing your senses.” And indeed, when we are very tired, we, as a rule, do not dream and become almost insensitive to external stimuli: noise, light, even pain.
Sechenov's research was continued by I.P. Pavlov. He came to the conclusion that there are innate reflexes, the occurrence of which does not require any special conditions, and acquired, arising during the adaptation of the body to the external environment.
If the release of saliva when food is served is a typical unconditioned reflex, and it is characteristic of all dogs, then saliva even at the sight of a helper is a typical conditioned reflex developed in individual animals. Hence the main difference between the two types: genetic or occurrence under the influence of the environment. In addition, unconditioned and conditioned reflexes differ in a number of indicators.
- Unconditioned are present in all individuals of the species, regardless of their living conditions; conditional, on the contrary, arise under the influence individual conditions life of the organism (this difference is clear from the name of each species).
- Unconditioned reactions are the foundation on which conditioned ones can be formed, but they need constant reinforcement.
- Reflex arcs of unconditioned reflexes are closed in the lower parts of the brain, as well as in the spinal cord. The conditioned arcs are formed in the cerebral cortex.
- Unconditioned reflex processes remain unchanged throughout a person’s life, although they can be somewhat transformed in the case of a serious illness. Conditional - arise and disappear. In other words, in one case reflex arcs permanent, in another – temporary.
From these differences it is easy to add up general characteristics unconditioned reflexes: they are hereditary, unchangeable, inherent in all representatives of the species and support the life of the organism in constant environmental conditions.
Where do they arise?
As already mentioned, both conditioned and unconditioned reflexes are possible thanks to the work of the central nervous system. Its most important components are the head and spinal cord. As an example of an unconditioned reflex for which the spinal cord is responsible, we can cite the well-known knee reflex.
Unconditioned reflexes of the brain are numerous. In the lower parts of this organ there are various reflex centers. So, if you move up from the spinal cord, the first is the medulla oblongata. Sneezing, coughing, swallowing, salivation - these reflex processes are possible precisely thanks to the work of the medulla oblongata.
Under the control of the midbrain - reactions that occur in response to visual or auditory impulses. This includes constriction or dilation of the pupil depending on the amount of light falling on it, a reflexive turn towards the source of sound or light. The effect of such reflexes extends only to unfamiliar stimuli.
That is, for example, when there are numerous sharp sounds, a person will each time turn to a new place where the noise originates, rather than continue to listen, trying to understand where the first sound came from. The so-called unconditioned reflex of straightening the posture is closed through the intermediate part of the brain. These are the muscle contractions with which our body responds to changes in posture; they allow the body to be held in a new position.
Classification
Classification of unconditioned reflexes is carried out according to different criteria. For example, there is a division that is understandable even to a non-specialist into simple, complex and extremely complex.
The classification is quite simple based on the body’s relationship to the stimulus. If you rely on it, unconditioned reflex reactions are divided into positive (search for food by smell) and negative (desire to escape from the source of noise).
By biological significance stand out the following types unconditioned reflexes:
- Nutritional (swallowing, sucking, salivation).
- Sexual (sexual arousal).
- Defensive or protective (the same withdrawal of hands or the desire to cover the head with hands if a person thinks that a blow is about to follow).
- Indicative (the desire to identify unfamiliar stimuli: turning your head towards a sharp sound or touch). They were already discussed when we talked about the reflex centers of the midbrain.
- Locomotor, that is, serving for movement (support the body in a certain position in space).
Very often in scientific literature there is a classification proposed by the Russian scientist P. V. Simonov. He divided all unconditioned reflexes into three groups: vital, role and self-development reflexes.
If the corresponding need is not satisfied, the physical existence of the organism ceases; another representative of the species is not needed to implement the reflex - these are the signs that unite all the reactions of this group.
Role-playing can be carried out, on the contrary, only through contact with another individual. These primarily include parental and sexual reflexes. IN last group includes such reflexes as play, research, and the reflex of imitation of another individual.
Of course, there are other classification options, as well as other views on the methods of division given here. And this is not surprising: there is rarely unanimity among scientists.
Features and meaning
As we have already said, the reflex arcs of unconditioned reflexes are constant, but they themselves can be active in different periods human life. For example, sexual reflexes appear when the body reaches a certain age. Other reflex processes, on the contrary, fade away after a certain period of time. Suffice it to recall the unconscious grasping of a baby by an adult’s finger when pressing on his palm, which disappears with age.
The importance of unconditioned reflexes is enormous. They help to survive not only an individual organism, but the entire species. They are most significant on early stages human life, when knowledge about the world has not yet been accumulated and the child’s activities are guided by reflex processes.
Moreover, according to latest research, certain unconditioned reflexes are carried out in the womb (for example, sucking). With age, more and more conditioned reflexes are added to the unconditioned ones, which allow a person to better adapt to a changing environment. Author: Evgenia Bessonova
Swallowing, salivation, rapid breathing due to lack of oxygen - all these are reflexes. They exist huge variety. Moreover, everyone individual person and animal they may differ. Read more about the concepts of reflex, reflex arc and types of reflexes further in the article.
What are reflexes
This may sound scary, but we do not have one hundred percent control over all our actions or the processes of our body. We are, of course, not talking about decisions to get married or go to university, but smaller, but very important actions. For example, about jerking our hand when accidentally touching a hot surface or trying to hold on to something when we slip. It is in such small reactions that reflexes appear, controlled by the nervous system.
Most of them are inherent in us at birth, others are acquired later. In a sense, we can be compared to a computer, into which, even during assembly, programs are installed in accordance with which it operates. Later, the user will be able to download new programs, add new action algorithms, but the basic settings will remain.
Reflexes are not limited to humans. They are characteristic of all multicellular organisms that have a CNS (central nervous system). Different kinds reflexes are carried out constantly. They contribute to the proper functioning of the body, its orientation in space, and help us quickly respond to danger. The absence of any basic reflexes is considered a disorder and can make life much more difficult.
Reflex arc
Reflex reactions occur instantly, sometimes you don’t have time to think about them. But despite everything apparent simplicity, they represent extremely complex processes. Even the most basic action in the body involves several parts of the central nervous system.
The stimulus acts on the receptors, the signal from them passes along nerve fibers and goes straight to the brain. There the impulse is processed and sent to the muscles and organs in the form direct guidance to an action, for example, “raise your hand,” “blink,” etc. The entire path that goes nerve impulse, is called a reflex arc. IN full version it looks something like this:
- Receptors are nerve endings that perceive a stimulus.
- Afferent neuron - transmits a signal from receptors to the center of the central nervous system.
- Interneuron - nerve center, is not involved in all types of reflexes.
- Efferent neuron - transmits a signal from the center to the effector.
- An effector is an organ that carries out a reaction.
The number of arc neurons may vary, depending on the complexity of the action. The information processing center can pass through either the brain or the spinal cord. The simplest involuntary reflexes are carried out by the spinal cord. These include changes in the size of the pupil when the lighting changes or withdrawal when pricked with a needle.
What types of reflexes are there?
The most common classification is the division of reflexes into conditioned and unconditioned, depending on how they were formed. But there are other groups, let’s look at them in the table:
Classification sign | Types of reflexes |
By nature of education | Conditional Unconditional |
According to biological significance | Defensive Approximate Digestive |
By type of executive body | Motor (locomotor, flexor, etc.) Vegetative (excretory, cardiovascular, etc.) |
By influence on the executive body | Exciting Brake |
By type of receptor | Exteroceptive (olfactory, cutaneous, visual, auditory) Proprioceptive (joints, muscles) Interoceptive (endings of internal organs). |
Unconditioned reflexes
Congenital reflexes are called unconditioned. They are transmitted genetically and do not change throughout life. Within them there are simple and complex species reflexes. They are most often processed in the spinal cord, but in some cases the cerebral cortex, cerebellum, brainstem, or subcortical ganglia may be involved.
A striking example unconditional reactions serves as homeostasis - the process of maintaining the internal environment. It manifests itself in the form of regulation of body temperature, blood clotting during cuts, increased breathing with increased amounts of carbon dioxide.
Unconditioned reflexes are inherited and are always tied to a specific species. For example, all cats land strictly on their paws; this reaction manifests itself in them already in the first month of life.
Digestive, orientation, sexual, protective - these are simple reflexes. They manifest themselves in the form of swallowing, blinking, sneezing, salivation, etc. Complex unconditioned reflexes manifest themselves in the form of individual forms of behavior, they are called instincts.
Conditioned reflexes
Unconditioned reflexes alone are not enough in the course of life. During our development and acquisition life experience conditioned reflexes often arise. They are acquired by each individual individually, are not hereditary and can be lost.
They are formed with the help of the higher parts of the brain on the basis of unconditioned reflexes and arise under certain conditions. For example, if you show an animal food, it will produce saliva. If you show him a signal (lamp light, sound) and repeat it every time food is served, the animal will get used to it. Next time, saliva will begin to be produced when the signal appears, even if the dog does not see the food. Such experiments were first carried out by the scientist Pavlov.
All types of conditioned reflexes are developed in response to certain stimuli and are necessarily reinforced by negative or positive experience. They underlie all our skills and habits. On the basis of conditioned reflexes, we learn to walk, ride a bicycle, and can acquire harmful addictions.
Excitation and inhibition
Each reflex is accompanied by excitation and inhibition. It would seem that these are absolutely opposite actions. The first stimulates the functioning of organs, the other is designed to inhibit it. However, they both simultaneously participate in the implementation of any types of reflexes.
Inhibition does not in any way interfere with the manifestation of the reaction. This nervous process It does not affect the main nerve center, but dulls the others. This happens so that the excited impulse reaches strictly for its intended purpose and does not spread to organs that perform the opposite action.
When bending the arm, inhibition controls the extensor muscles; when turning the head to the left, it inhibits the centers responsible for turning to the right. The absence of inhibition would lead to involuntary and ineffective actions, which would only get in the way.
Animal reflexes
The unconditioned reflexes of many species are very similar to each other. All animals have a feeling of hunger or the ability to secrete digestive juice at the sight of food; when hearing suspicious sounds, many listen or begin to look around.
But some reactions to stimuli are the same only within a species. For example, hares run away when they see an enemy, while other animals try to hide. Porcupines, equipped with spines, always attack a suspicious creature, a bee stings, and possums pretend to be dead and even imitate the smell of a corpse.
Animals can also acquire conditioned reflexes. Thanks to this, dogs are trained to guard the house and listen to the owner. Birds and rodents easily get used to people feeding them and do not run away at the sight of them. Cows are very dependent on their daily routine. If you disrupt their routine, they produce less milk.
Human reflexes
Like other species, many of our reflexes appear in the first months of life. One of the most important is sucking. With the smell of milk and the touch of the mother's breast or a bottle that imitates it, the baby begins to drink milk from it.
There is also a proboscis reflex - if you touch the baby’s lips with your hand, he sticks them out with a tube. If the baby is placed on his stomach, his head will necessarily turn to the side, and he himself will try to rise. With the Babinski reflex, stroking the baby's feet causes the toes to fan out.
Most of the very first reactions accompany us only for a few months or years. Then they disappear. Among the types of human reflexes that remain with him for life: swallowing, blinking, sneezing, olfactory and other reactions.
- 1. Introduction3
- 2. Physiology of unconditioned reflexes3
- 3. Classification of unconditioned reflexes5
- 4. The importance of unconditioned reflexes for the body7
- 5. Conclusion7
References8
Introduction
Unconditioned reflexes are hereditarily transmitted (innate), inherent to the entire species. Execute protective function, as well as the function of maintaining homeostasis.
Unconditioned reflexes are an inherited, unchangeable reaction of the body to external and internal signals, regardless of the conditions of occurrence and course of reactions. Unconditioned reflexes ensure the body's adaptation to constant environmental conditions. Are species behavioral sign. The main types of unconditioned reflexes: food, protective, orienting.
Example protective reflex is a reflexive withdrawal of the hand from a hot object. Homeostasis is maintained, for example, by a reflex increase in breathing when there is an excess of carbon dioxide in the blood. Almost every part of the body and every organ is involved in reflex reactions.
Physiology of unconditioned reflexes
An unconditioned reflex is an innate response of the body to irritation when mandatory participation central nervous system (CNS). In this case, the cerebral cortex does not directly participate, but exercises its highest control over these reflexes, which allowed I.P. Pavlov to assert the presence of a “cortical representation” of each unconditioned reflex. Unconditioned reflexes are the physiological basis:
1. Human species memory, i.e. congenital, inherited, constant, common to the entire human species;
2. Inferior nervous activity(NND). NND from the point of view of unconditioned reflexes is an unconditioned reflex activity that provides the body with the unification of its parts into a single functional whole. Another definition of NND. NND is a set of neurophysiological processes that ensure the implementation of unconditioned reflexes and instincts.
Protozoa neural networks, or arcs (according to Sherrington), involved in unconditioned reflexes, are closed in the segmental apparatus of the spinal cord, but can be closed higher (for example, in subcortical ganglia or in the cortex). Other parts of the nervous system are also involved in reflexes: the brain stem, cerebellum, and cerebral cortex.
The arcs of unconditioned reflexes are formed at the time of birth and remain throughout life. However, they can change under the influence of illness. Many unconditioned reflexes appear only at a certain age; Thus, the grasping reflex characteristic of newborns fades away at the age of 3-4 months.
There are monosynaptic (involving the transmission of impulses to the command neuron through one synaptic transmission) and polysynaptic (involving the transmission of impulses through chains of neurons) reflexes.
Approximate unconditioned reflexes, occurring with the direct participation of the cerebral cortex, are physiological mechanisms of human cognitive activity and involuntary attention. In addition, the extinction of orienting reflexes is physiological basis addiction and boredom. Habituation is the extinction of the orienting reflex: if the stimulus is repeated many times and does not have special significance for the body, the body stops reacting to it, addiction develops. So, a person living on a noisy street gradually gets used to the noise and no longer pays attention to it.
Instincts are a form of innate behavior. Physiological mechanism they are a chain of innate unconditioned reflexes, into which, under the influence of individual life conditions, links of acquired conditioned reflexes can be “woven”.
Rice. 1. Scheme of organization of instinctive behavior: S - stimulus, P - reception, P - behavioral act; the dotted line is the modulating influence, the solid line is the activity of the modulating system as an evaluative authority.
Reflection as the essence of the psyche occurs on different levels. There are three levels of brain activity: specific, individual and socio-historical. Reflection at the species level is carried out by unconditioned reflexes.
In development theoretical foundations The concept of “drive and drive-reflex” by the Polish physiologist and psychologist J. Konorski played a significant role in the organization of behavior. According to the theory of Yu. Konorsky, brain activity is divided into executive and preparatory, and all reflex processes fall into two categories: preparatory (incentive, drive, motivational) and executive (consummatory, consummatory, reinforcing).
Executive functioning involves many specific responses to many specific stimuli, so this activity is provided by the cognitive or gnostic system, which includes the stimulus recognition system. Preparatory activities associated with less specific reactions and in to a greater extent controlled by the internal needs of the body. It is anatomically and functionally different from the system responsible for perception and cognitive activity, training, and is called by Yu. Konorsky an emotive, or motivational system.
The cognitive and emotive systems are served by different brain structures.
Most unconditioned reflexes are complex reactions, which includes several components. So, for example, with an unconditioned defensive reflex caused in a dog by strong electrodermal irritation of the limb, along with defensive movements, breathing also increases and increases, cardiac activity accelerates, vocal reactions appear (squealing, barking), the blood system changes (leukocytosis, thrombocytosis and etc.). The food reflex also distinguishes between its motor (grasping food, chewing, swallowing), secretory, respiratory, cardiovascular and other components.
So, the most complex unconditioned reflexes are an innate holistic behavioral act, a systemic morphophysiological formation that includes stimulating and reinforcing components (preparatory and executive reflexes). Instinctive behavior is implemented by external and internal determinants by “assessing” the relationships between significant components of the environment and internal state organism determined by actualized need.
Classification of unconditioned reflexes
The entire set of unconditioned and conditioned reflexes formed on their basis is accepted according to their functional significance divided into a number of groups. The main ones are nutritional, defensive, sexual, statokinetic and locomotor, orientation, maintaining homeostasis and some others. Food reflexes include reflex acts of swallowing, chewing, sucking, salivation, secretion of gastric and pancreatic juice, etc. Defensive reflexes are reactions to eliminate damaging and painful stimuli. The group of sexual reflexes includes all reflexes associated with sexual intercourse; This group also includes the so-called parental reflexes associated with feeding and nursing the offspring. Statokinetic and locomotor reflexes are reflex reactions of maintaining a certain position and movement of the body in space. Reflexes that support the preservation of homeostasis include thermoregulatory, respiratory, cardiac and those vascular reflexes that help maintain constancy blood pressure, and some others. Special place Among the unconditioned reflexes, the orienting reflex ranks. This is a reflex to novelty.
It occurs in response to any sufficiently rapid vibration. environment and is expressed externally in alertness, listening to a new sound, sniffing, turning the eyes and head, and sometimes the entire body towards the emerging light stimulus, etc. The implementation of this reflex provides a better perception of the active agent and has important adaptive significance. This reaction is innate and does not disappear when complete removal cerebral cortex in animals; it is also observed in children with underdeveloped cerebral hemispheres- anencephals. The difference between the orienting reflex and other unconditioned reflex reactions is that it fades away relatively quickly with repeated applications of the same stimulus. This feature of the orientation reflex depends on the influence of the cerebral cortex on it.
Rice. 1. Comparison of the most complex unconditioned reflexes (instincts) of higher animals with human needs: double arrows - phylogenetic connections of the most complex reflexes of animals with human needs, dotted - the interaction of human needs, solid - the influence of needs on the sphere of consciousness
The importance of unconditioned reflexes for the body
The meaning of unconditioned reflexes:
♦ maintaining a constant internal environment (homeostasis);
♦ maintaining the integrity of the body (protection from damaging environmental factors);
♦ reproduction and preservation of the species as a whole.
Conclusion
Unconditioned reflexes, the formation of which is completed in postnatal ontogenesis, are genetically predetermined and strictly adjusted to certain, appropriate this species environmental conditions.
Congenital reflexes are characterized by a stereotypical species-specific sequence of implementation of a behavioral act. They arise at their first need, when a stimulus “specific” to each of them appears, thereby ensuring the consistency of fulfillment of the most vital important functions organism regardless of random, transient environmental conditions. Characteristic feature unconditioned reflexes is that their implementation is determined by both internal determinants and an external stimulus program.
As noted by P.V. Simonov, the definition of an unconditioned reflex as hereditary, unchangeable, the implementation of which is machine-like and independent of the achievements of its adaptive goal, is usually exaggerated. Its implementation depends on the existing functional state of the animal and correlates with the dominant this moment need. It may fade or intensify.
Satisfying the most diverse needs would have been impossible if it had not arisen in the process of evolution specific reaction overcoming, freedom reflex. The fact that the animal resists coercion, attempts to limit it motor activity, Pavlov looked much deeper than just a variety defensive reaction. The freedom reflex is an independent active form behavior for which an obstacle serves as no less an adequate stimulus than food for food search, pain for a defensive reaction, and a new and unexpected stimulus for an orienting reflex.
Bibliography
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- 2. Danilova, A.L. Krylova Physiology of higher nervous activity. - Rostov n/a: “Phoenix”, 2005. - 478
- 3. Psychophysiology /ed. Alexandrova Yu.I. St. Petersburg, publishing house "Peter" 2006
- 4. Tonkonogiy I.M., Pointe A. Clinical neuropsychology. 1st edition, Publisher: PETER, PUBLISHING HOUSE, 2006
- 5. Shcherbatykh Yu.V. Turovsky Ya.A. Anatomy of the central nervous system for psychologists: Tutorial. St. Petersburg: Peter, 2006. - 128 p.
Reflex- this is the body's response to irritation of receptors, carried out nervous system. The path along which the nerve impulse passes during the implementation of the reflex is called.
The concept of “reflex” was introduced by Sechenov, he believed that “reflexes form the basis of the nervous activity of humans and animals.” Pavlov divided reflexes into conditioned and unconditioned.
Comparison of conditioned and unconditioned reflexes
| unconditional | conditional |
| present from birth | acquired during life |
| do not change or disappear during life | may change or disappear during life |
| identical in all organisms of the same species | Each organism has its own, individual |
| adapt the body to constant conditions | adapt the body to changing conditions |
| reflex arc passes through the spinal cord or brain stem | temporary connection is formed in the cerebral cortex |
| Examples | |
| salivation when lemon enters mouth | salivation at the sight of lemon |
| newborn sucking reflex | 6 month old baby's reaction to a bottle of milk |
| sneezing, coughing, pulling your hand away from the hot kettle | reaction of a cat/dog to a name |
Development of a conditioned reflex
Conditional (indifferent) the stimulus must precede unconditional(causing an unconditioned reflex). For example: a lamp is lit, after 10 seconds the dog is given meat.
Inhibition of conditioned reflexes
Conditional (non-reinforcement): the lamp lights up, but the dog is not given meat. Gradually, salivation when the lamp is turned on stops (the conditioned reflex fades).
Unconditional: During the action of a conditioned stimulus, a powerful unconditioned stimulus arises. For example, when the lamp is turned on, the bell rings loudly. No saliva is produced.
Choose the one that suits you best correct option. The centers of conditioned reflexes, in contrast to unconditioned ones, are located in humans in
1) cerebral cortex
2) medulla oblongata
3) cerebellum
4) midbrain
Answer
Choose one, the most correct option. Salivation in a person at the sight of a lemon is a reflex
1) conditional
2) unconditional
3) protective
4) approximate
Answer
Choose three options. The peculiarity of unconditioned reflexes is that they
5) are congenital
6) are not inherited
Answer
Choose three correct answers out of six and write down the numbers under which they are indicated. Unconditioned reflexes that ensure life activity human body,
1) are developed in the process of individual development
2) formed in the process of historical development
3) are present in all individuals of the species
4) strictly individual
5) formed under relatively constant environmental conditions
6) are not congenital
Answer
Choose three correct answers out of six and write down the numbers under which they are indicated. The peculiarity of unconditioned reflexes is that they
1) arise as a result of repeated repetition
2) are a characteristic characteristic of an individual individual of the species
3) are genetically programmed
4) are characteristic of all individuals of the species
5) are congenital
6) build skills
Answer
Choose one, the most correct option. What are the features of spinal reflexes in humans and mammals?
1) acquired during life
2) are inherited
3) are different in different individuals
4) allow the organism to survive in changing environmental conditions
Answer
Choose one, the most correct option. The extinction of a conditioned reflex when it is not reinforced by an unconditioned stimulus is
1) unconditional inhibition
2) conditioned inhibition
3) rational action
4) conscious action
Answer
Choose one, the most correct option. Conditioned reflexes of humans and animals provide
1) adaptation of the body to constant environmental conditions
2) adaptation of the body to the changing external world
3) development of new motor skills by organisms
4) discrimination by animals of the trainer’s commands
Answer
Choose one, the most correct option. A baby's reaction to a bottle of milk is a reflex that
1) inherited
2) is formed without the participation of the cerebral cortex
3) acquired during life
4) persists throughout life
Answer
Choose one, the most correct option. When developing a conditioned reflex, the conditioned stimulus must
1) act 2 hours after unconditional
2) come immediately after the unconditional
3) precede the unconditional
4) gradually weaken
Answer
1. Establish a correspondence between the meaning of the reflex and its type: 1) unconditional, 2) conditional. Write numbers 1 and 2 in the correct order.
A) provides instinctive behavior
B) ensures the adaptation of the organism to the environmental conditions in which many generations of this species lived
C) allows you to gain new experience
D) determines the behavior of the organism in changed conditions
Answer
2. Establish a correspondence between the types of reflexes and their characteristics: 1) conditional, 2) unconditional. Write numbers 1 and 2 in the order corresponding to the letters.
A) are congenital
B) adaptation to new emerging factors
C) reflex arcs are formed in the process of life
D) are the same in all representatives of the same species
D) are the basis of learning
E) are constant, practically do not fade during life
Answer
Choose one, the most correct option. Conditioned (internal) inhibition
1) depends on the type of higher nervous activity
2) appears when a stronger stimulus occurs
3) causes the formation of unconditioned reflexes
4) occurs when the conditioned reflex fades
Answer
Choose one, the most correct option. The basis of nervous activity in humans and animals is
1) thinking
2) instinct
3) excitement
4) reflex
Answer
1. Establish a correspondence between the examples and types of reflexes: 1) unconditional, 2) conditional. Write numbers 1 and 2 in the correct order.
A) withdrawing a hand from the fire of a burning match
B) a child crying at the sight of a man in a white coat
C) a five-year-old child reaching out to the sweets he saw
D) swallowing pieces of cake after chewing them
D) salivation at the sight of a beautifully set table
E) downhill skiing
Answer
2. Establish a correspondence between the examples and the types of reflexes that they illustrate: 1) unconditional, 2) conditioned. Write numbers 1 and 2 in the order corresponding to the letters.
A) sucking movements of the child in response to touching his lips
B) constriction of the pupil illuminated by the bright sun
C) performing hygiene procedures before bed
D) sneezing when dust enters the nasal cavity
D) secretion of saliva to the clink of dishes when setting the table
E) roller skating
Answer
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