Conditioned and unconditioned reflexes presentation. Presentation - inhibition of conditioned reflexes. Description of the presentation Presentation Unconditioned and conditioned reflexes on slides

Conditioned reflexA conditioned reflex is a reaction of the body,
acquired during life as a result
combinations of indifferent (indifferent)
stimulus with the unconditioned.
The physiological basis of the conditioned
reflex constitutes the process of closure
temporary connection. A temporary connection is
a set of neurophysiological,
biochemical and ultrastructural
brain changes that occur during
combinations of conditional and unconditional
irritants and forming certain
relationships between different
brain formations.

Stimulus

Stimulus - any material agent, external or internal,
conscious or unconscious, acting as a condition for subsequent
states of the body. Signal stimulus (also indifferent) a stimulus that previously did not cause a corresponding reaction, but when
certain conditions for the formation of a conditioned reflex, which begins it
call. Such an irritant actually causes
indicative unconditioned reflex. However, when repeated many times
irritation, the orienting reflex begins to weaken, and then completely
disappears.
Stimulus - an influence that determines the dynamics of mental states
individual (reaction) and related to it as cause and effect.
Reaction - any response of the body to a change in external or internal
environment from the biochemical reaction of an individual cell to a conditioned reflex.

Stages and mechanism of conditioned reflex
1. Stage during generalization – characterized by pronounced
concentration of excitation (main image, in the projection zones of the cortex
conditioned and unconditional stimuli) and the absence of conditioned
behavioral reactions.
2. The stage of generalization is based on the process of “diffuse”
propagation (irradiation) of excitation. Conditioned reactions to
signal and other stimuli (afferent generalization) + in
intervals between presentations of the conditioned stimulus
(intersignal reactions). There is a distant
synchronization of biopotentials - synchronization
bioelectrical activity in many areas of the cortex and
subcortical formations.
3. Specialization stage - when intersignal reactions fade away and
a conditioned response occurs only to a signal stimulus.
(Changes in biocurrents are more limited and confined mainly to
to the action of a signal stimulus. This process ensures
differentiation, fine discrimination of stimuli, specialization
conditioned reflex skill).

reflex
For the formation of a conditioned reflex it is necessary to comply
the following rules:
1. An indifferent stimulus must have sufficient
force to excite certain receptors. Receptor –
this is a peripheral specialized part of the analyzer,
through which the influence of external stimuli
the world and the internal environment of the body is transformed into
process nervous excitement. The analyzer is nervous
apparatus performing the function of analysis and synthesis
irritants. It includes the receptor part,
conducting pathways and the analyzer nucleus in the cerebral cortex.
However, an excessively strong stimulus may not
cause a conditioned reflex. Firstly, its action
will cause, according to the law of negative induction, a decrease
cortical excitability, which will lead to a weakening of BR,
especially if the strength of the unconditioned stimulus was
small. Secondly, an excessively strong stimulus can
cause a focus in the cerebral cortex instead of a focus of excitation
braking, in other words, bring the appropriate
area of the cortex into a state of extreme inhibition.

Rules for the formation of a conditioned reflex

Conditional formation rules
reflex
2. The indifferent stimulus must
reinforced by an unconditional stimulus, and
it is desirable that it precedes it somewhat, or
was presented simultaneously with the last one. When in action
first the unconditioned stimulus, and after it
if an indifferent conditioned reflex is formed,
it usually remains very fragile. At
simultaneous activation of both stimuli
It is much more difficult to develop a conditioned reflex.
3. It is necessary that the stimulus used in
as a conditional, was weaker than the unconditional.
4. To develop a conditioned reflex it is necessary
also the normal functioning of cortical and
subcortical structures and the absence of significant
pathological processes in the body.
5. To develop a conditioned reflex it is necessary
absence of strong extraneous stimuli.

General properties conditioned reflexes
Despite certain differences, conditional
reflexes are characterized by the following general
properties (signs):
1. all conditioned reflexes represent one of
forms of adaptive reactions of the body to
changing environmental conditions;
2. conditioned reflexes belong to the category
acquired during individual life
reflex reactions and differ individually
specificity;
3. all types of conditioned reflex activity are
signal
precautionary nature;
4. conditioned reflex reactions are formed on the basis
unconditioned reflexes; without
reinforcement of conditioned reflexes over time
weakened and suppressed.

The mechanism of formation of a conditioned reflex

The mechanism of conditional formation
reflex
1. Theory of E.A. Asratyan. E.A.Asratyan, studying unconditioned reflexes,
came to the conclusion that the central part of the arc of the unconditioned reflex
not unilinear, it does not pass through just one level
brain, but has a multi-level structure, that is, the central part
The arc of the unconditioned reflex consists of many branches that
pass through various levels of the central nervous system (spinal cord, medulla oblongata
brain, stem sections, etc.). Moreover, the highest part of the arc
passes through the cerebral cortex, through the cortical
representation of this unconditioned reflex and personifies
corticolization of the corresponding function. Next Asratyan
suggested that if the signal and reinforcing stimuli
cause their own unconditioned reflexes, then they constitute
neurosubstrate of the conditioned reflex. Indeed, conditional
the stimulus is not absolutely indifferent, since it itself
causes a certain unconditioned reflex reaction, indicative, and with significant strength this stimulus
causes unconditional visceral and somatic reactions. Arc
the orienting reflex also has a multi-level structure with
its cortical representation.
Consequently, when an indifferent stimulus is combined with
unconditional (reinforcing) a temporary connection is formed between
cortical and subcortical branches of two unconditioned reflexes
(indicative and reinforcing), that is, the formation of conditional
reflex is a synthesis of two or more unconditioned reflexes

E.A.Asratyan

Theory V.S. Rusinova.

2.
According to the teaching
B.S.Rusinova conditioned reflex
first becomes dominant, and
then - a conditioned reflex. If
using direct polarization
create a focus area of the cortex
excitation, then a conditioned reflex reaction can be
call any indifferent
irritant.

The mechanism of conditioned reflex activity

Research has shown that there are two mechanisms of conditioned reflex activity:
1. superstructural, regulating the state of the brain and creating
a certain level of excitability and performance of the nervous
centers;
2. trigger, which initiates one or another conditioned reaction.
The relationship between the left and right hemispheres in the development of conditioned
reflex is carried out through the corpus callosum, camissura,
intertubercular fusion, quadrigeminal and reticular formation
brain stem. At the cellular and molecular levels, temporal communication
is closed using memory mechanisms. At the beginning of production
conditioned reflex communication is carried out using mechanisms
short-term memory - the spread of excitation between two
excited cortical centers. Then she goes to
long-term, that is, structural changes occur in
neurons.

Scheme of the arc of a conditioned reflex with two-way communication (according to E.A. Asratyan)

Diagram of the arc of a conditioned reflex with two-way communication (according to
E.A. Asratyan): a - cortical center of the blink reflex; b -
cortical center of the food reflex; c, d - subcortical centers
blinking and food reflexes, respectively; I - straight
temporary connection; II - time feedback

Reflex arc diagrams

Schemes of reflex arcs: A – two-neuron reflex arc; B –
three-neuron reflex arc:
1 – receptor in muscle and tendon; 1a – receptor in the skin; 2 –
afferent fiber; 2a – neuron of the spinal ganglion; 3 –
interneuron; 4 – motor neuron; 5 – efferent fiber; 6 –
effector (muscle).

Prepared by a student of group 21
Bychkova Ekaterina

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Slide captions:

Reflexes.

The concept of reflex. A reflex is the body's response to stimulation carried out by the nervous system. Reflexes can be innate - instincts - and conditioned, that is, acquired during life. Conditioned reflexes are not inherited. Congenital reflexes are called unconditioned. They are inherited.

Unconditioned reflexes. Available from birth. They do not change or disappear during life. Adapt the body to constant conditions. Same for all organisms of a given species

Examples of unconditioned reflexes

Sneezing is a protective innate reflex.

Conditioned reflexes. Acquired during life. May change and disappear as conditions change. Each organism produces its own. Adapt the body to changing conditions.

Examples of conditioned reflexes in animals

Training is based on a conditioned reflex

Development of a conditioned reflex

Conclusions. The functioning of the nervous system is based on a reflex - a response to irritation. Reflexes are divided into conditioned, developed during life, and innate or unconditioned. Unconditioned reflexes help us survive in difficult conditions. Thanks to conditioned reflexes, animals acquire skills and abilities.

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Comparison of conditioned and unconditioned reflexes

Reflexes are the body’s responses to changes in the environment or internal environment; manifested by the occurrence or cessation of any activity of the body, contraction or relaxation of muscles, narrowing or dilation of blood vessels. Reflexes are characteristic only of organisms that have a nervous system. “In the life of a complex organism,” wrote the great Russian physiologist I.P. Pavlov, the reflex is the most essential and most frequent nervous phenomenon. With its help, a constant, correct and accurate relationship between the parts of the organism and the relationship of the whole organism is established.

It is customary to divide all reflexes into conditioned and unconditioned. A living organism is born with a set of innate reflexes. For example, in a newborn, sucking movements occur the moment something touches his mouth. Innate reflexes are distinguished by great constancy: in response to the same irritation, regardless of other conditions, a strictly defined reaction occurs. I.P. Pavlov called such reflexes

unconditional.

Over time, more complex behavior is built on the basis of unconditioned reflexes: sucking movements, for example, occur only in response to irritations reinforced by food. The child gets used to certain feeding hours, and saliva corresponding to the amount and nature of food begins to be released not only after, but also before food enters the mouth.

In an adult, salivation may occur at the mere sight or smell of food. These kinds of reflexes are acquired in the process of individual experience of each individual animal or person; they completely depend on the specific conditions of existence for each. These reflexes I.P. Pavlov called them conditional. With changes to environment reflexes also change. It is thanks to conditioned reflexes that the body is able to quickly rebuild its behavior.

Unconditioned reflexes

Lower nervous activity is called unconditioned reflex activity, and its individual reactions are called unconditioned reflexes. With a sharp change in environmental conditions, the unconditioned reflex becomes a poor helper. For example, hedgehogs are characterized by a defensive unconditioned reflex: curl up into a ball and expose their spines. For many millennia, he helped them out, but in the second half of the 20th century, according to zoologists, this reflex brought them to the brink of extinction, because hedgehogs that go out at night onto roads that retain heat for a long time to warm up, do not run away when a car approaches , but they are trying

defend themselves as of old with the same thorns and, of course, die under the wheels.

An attempt to adapt to dramatically changed conditions using unconditionally reflexive behavior can lead the body to death. Moreover, since all representatives of a given biological species have the same unconditioned reflexes, with a sharp change in climate or other factors, not one organism, but many individuals may die. In single-celled organisms, worms, mollusks and arthropods, for example, death large number individuals are replenished by a huge reproduction rate. Higher animals and humans adapt to changing conditions in a completely different way. In these species, based on the lower nervous activity new adaptation mechanisms have formed - higher nervous activity. With its help, living organisms acquired the ability to respond not only to the direct action of biologically significant agents (food, sexual, defensive), but also to their distant signs, identifying from the chaos of the environment connections in time between a biologically important phenomenon and the events that naturally preceded it.

Conditioned reflexes

The conditioned reflex is an extremely complex phenomenon. It is developed on the basis of unconditioned reflexes. For its formation, a combination in time of any change in the environment (or in the internal state of the organism), perceived by the animal, with the implementation of some unconditioned reflex is necessary. Only under this condition can this change itself become a stimulus causing a conditioned reflex. Such a stimulus is called a conditioned or signal. For example, the knocking of a bowl from which a dog was fed causes salivation only when these sounds

coincided with food. This is the classic scheme for the formation of a conditioned reflex.

However, observations show that this requires a number of other conditions. For example, a fed dog will not respond to a conditioned stimulus. This means that a conditioned reflex can only arise against the background of a corresponding biological need. In particular, for the implementation of a conditioned food reflex, a feeling of hunger is necessary. Such states subjectively express an objective need, and it is they that contain the motivation for further behavior aimed at satisfying the need (in this case, food). That's why they are called motivations. Thus, it is not the objective conditioned stimulus, but primarily the prevailing motivation that provides the possibility of realizing the conditioned reflex.

The structural basis of all reflexes is the so-called reflex arc. It consists of receptors that perceive irritation, sensory, or afferent, fibers through which signals enter the central nervous system; intercalary neurons that process received information; efferent nerve fibers that transmit motor commands to the periphery. The idea of a reflex arc was introduced into science more than 300 years ago by the French scientist R. Descartes.

Higher nervous activity refers to those functions of the brain that are associated with the inner world of a person, his psyche. VND is the activity of the higher parts of the central nervous system, ensuring the most perfect adaptation of animals and humans to the external environment. The study of higher nervous activity in Russia is associated primarily with the names of two great scientists: Ivan Mikhailovich Sechenov (1829-1905) and Ivan Petrovich Pavlov (1849-1936). The merit of I.M. Sechenov is that he proved that the brain can both enhance the reflexes of the spinal cord and inhibit them. It was the discovery of central inhibition that brought fame and world recognition to I.M. Sechenov. He showed that the higher parts of the nervous system are capable of regulating the work of the lower parts. This proved the multi-level organization of brain function. The higher the part of the brain is located, the more complex functions he fulfills. I.P. Pavlov continued his research and found that all reflexes can be divided into two large groups. Congenital (unconditioned) reflexes acquired (conditioned) IP Pavlov associated the formation of conditioned reflexes with the work of the cerebral cortex. They arise under the obligatory condition of a combination of any irritation, even a minor one, with vital irritations (for example, food, pain, danger) and become their signals. The concept of congenital and acquired forms of behavior. The need for something to maintain the life and development of the organism causes a special state called need. A complex complex of adaptive motor acts aimed at satisfying the body’s needs and manifested in purposeful activity is called behavior. Behavior is a combination of physiological and mental processes. Behavior Innate Acquired No clear boundary Innate behavior refers to those forms of behavior that are genetically programmed and which are almost impossible to change. Acquired (as a result of learning) are all forms of behavior that are formed as a result of the individual experience of a living organism. Unconditioned reflexes, their characteristics and classification Unconditioned reflexes (species reflexes) are relatively constant, stereotypical, innate, genetically fixed reactions of the body to internal and external stimuli (stimuli), carried out with the participation of the central nervous system (CNS). The term “unconditioned reflex” was introduced by I.P. Pavlov - an obligatory species characteristic - has ready-made reflex arcs. - carried out by spinal or cranial reflex arcs. - centers are located in the spinal cord and in the brain stem, i.e. in the lower parts of the central nervous system. - the participation of the cerebral cortex is not necessary. - feedback – information about the results and degree of success of the action taken. Thanks to unconditioned reflexes, the integrity of the body is preserved, the constancy of the internal environment is maintained, and reproduction occurs. Unconditioned reflexes underlie all behavioral reactions of animals and humans. Classification of unconditioned reflexes (I.P. Pavlov) – food (swallowing, sucking, etc.); – sexual (“tournament fights”); – protective (coughing, sneezing, blinking, etc.); – indicative (alertness, listening, turning the head to the source of sound, etc.) The emergence of an internal need is a condition for the implementation of an unconditioned reflex Instincts and their characteristics Instinct (from Lat. instinctus - urge) is a complex innate form of behavior that occurs in response to certain environmental changes and has great importance for the survival of the organism. - specific for each species - a whole chain of reflex acts sequentially connected with each other. Examples: the construction of nests by birds, a dam by beavers, etc. This instinct manifested the following chain of innate reflexes: birth --> CO2 --> inhale --> cry. Instinctive behavior provides the body with a set of ready-made behavioral reactions, which allows the economical use of nerve cells. Answer question No. 2 on page 106 using the textbook text. Innate trigger mechanism Acquired forms of behavior. The basis of acquired forms of behavior is learning. Learning is a process based on individual experience that leads to adaptive changes in the behavior of an individual. Basic methods of learning Habituation, or habituation, is a process as a result of which already existing reactions are lost. This is how the cubs of the South African black-footed cat react to the first meeting with a person: bared teeth and flattened ears are a sign of anxiety. After the photographer began to appear every day, this reaction faded away. Conditioned reflexes are individually acquired systemic adaptive reactions of animals and humans, arising on the basis of the formation of a temporary connection between a conditioned stimulus and an unconditioned reflex act. The term “conditioned reflex” - P. Pavlov in 1903 - is strictly individual and unstable - The arcs of acquired reflexes are closed in the cerebral cortex and are temporary. Trial and error method Skinner's camera Insight (from the English insight - intuition, understanding) is an animal's sudden solution to a relatively complex task after a few random, chaotic attempts to achieve the desired result. Köhler's experiment on chimpanzees Imprinting, or imprinting (from the English imprint - to imprint, imprint), is the formation in the early period of development of an individual of stable individual selectivity to external stimuli. 30s XX century Konrad Lorenz. An apparatus used to study imprinting. It consists of a treadmill along the circumference of which a duck decoy moves. The duckling follows the decoy. Control equipment in the foreground Conditioned reflexes are individually acquired systemic adaptive reactions of animals and humans, arising on the basis of the formation of a temporary connection between a conditioned stimulus and an unconditioned reflex act. I.P. Pavlov developed a method for the formation of conditioned reflexes. Experiment on the development of conditioned reflexes according to I.P. Pavlova. On the left is the internal part of the experimental chamber, on the right is the external part. Conditions necessary for the formation of the catch reflex 1. The presence of two stimuli: indifferent (indifferent), which they want to make conditional, and unconditional, causing some activity of the body. 2. An indifferent stimulus (light, sound, etc.) must precede the unconditional one and accompany the action of the latter for some time. 3. The unconditioned stimulus must be stronger than the conditioned one. 4. Lack of distracting extraneous stimuli. 5. Active state of the cortex Development of a conditioned reflex 1. The dog sees the light bulb on, but does not react to it in any way. There is no reflex. 2 – Visual center in the cerebral cortex, 4 – Salivary gland. 2. 1 – Salivation center in the subcortex, 3 – Salivation center in the cerebral cortex, 4 – Salivary gland. A bowl full of food was placed in front of the dog. The dog begins to eat. The unconditioned reflex turns on. A signal is sent from the dog’s olfactory receptors to the brain - from the subcortex to the cerebral cortex and back, and then to the dog’s salivary glands. Saliva begins to flow. 3. 1 – Salivation center in the subcortex, 2 – Visual center in the cerebral cortex, 3 – Salivation center in the cerebral cortex, 4 – Salivary gland. The dog eats from a bowl. There is a light bulb in her field of vision as she eats. Information about the light bulb being turned on is transmitted from the visual receptors to the visual center of the dog’s brain. If the light comes on dozens of times in a row every time the dog eats, a new connection will be formed in his brain between the visual center and the salivation center. This way the dog will acquire a conditioned reflex that starts working when the light bulb is turned on. 4. 1 – Salivation center in the subcortex, 2 – Visual center in the cerebral cortex, 3 – Salivation center in the cerebral cortex, 4 – Salivary gland. Now, when the light bulb is turned on, the dog salivates, even if there is no bowl of food in front of him. A nerve impulse is transmitted from the eyes to the brain, which passes from the visual center to the salivary center of the cerebral cortex, then to the subcortex and from there to the dog’s salivary gland. General signs of conditioned reflexes are absent in newborns; – are an individual’s highest adaptation to changing living conditions; – carried out by the highest department of the central nervous system; – acquired through the formation of temporary neural connections and are lost if the environmental conditions that caused them have changed; – represent a warning signal reaction. A dynamic stereotype is the ability of the brain to combine a number of individual reflex acts into a system. - Human habits, daily routine, ability to skate, bike, ski - Plays a big role in the formation of a variety of work, sports, and play skills in humans and in the behavior of animals, if the activity is monotonous and often repeated. - Ensures the body’s adaptation to stable or habitually changing environmental conditions. - The ability for dynamic changes weakens with age. Rational activity is the ability of animals to grasp patterns connecting objects and phenomena in the environment, as well as to use knowledge of these patterns in new conditions. - The more developed the nervous system, the higher the level of rational activity. - Highest form adaptation to environmental conditions. Excitation and inhibition Excitation is an active state of nervous tissue in response to the action of various stimuli of sufficient strength. Inhibition is an active nervous process leading to inhibition of excitation. Types of unconditional (congenital) inhibition - transcendental (protective) inhibition - external inhibition - some innate reflexes in which certain stimuli cause the cessation of certain actions Types of conditioned (acquired) inhibition - Extinction inhibition - Differentiative, or discriminative, inhibition - Delayed inhibition Tasks Conditional inhibition reflex If a dog that has developed a food conditioned reflex to a light bulb is not fed after turning on the light, then after a while it will stop giving a food conditioned reflex reaction to the light and the conditioned reflex will fade. The extinction of conditioned reflexes is a biologically important adaptation. Thanks to it, the body stops wasting energy by reacting to a signal that has lost its meaning. Without inhibition, it would be impossible for the body to adapt to changing environmental conditions. Law of Mutual Induction The focus of excitation “induces” the process of inhibition on neighboring or competing areas. Dual images Different forms of inhibition I.M. Sechenov discovered central inhibition. I.P. Pavlov found out how the processes of excitation and inhibition interact with each other. He showed that there is innate inhibition and conditioned inhibition acquired during life. Innate inhibition includes external inhibition. The appearance of any other, stronger stimulus causes a new reflex in the body, and the previous one ceases its activity according to the law of mutual induction. With the help of external inhibition, the action that was performed before is automatically interrupted, and space is given for the functioning of new reflexes or other types of activity. Acquired inhibition refers to internal inhibition that occurs when a conditioned reflex is not reinforced, for example, when it fades. Dominant Behavior is determined by life needs. When the need intensifies, a temporary dominant in the central nervous system a source of excitement aimed at satisfying precisely this need. Alexey Alekseevich Ukhtomsky (1875-1942) Russian physiologist A.A. Ukhtomsky called such a mechanism of temporary dominance of excitation dominant. The dominant focus is distinguished by a number of features: 1 - it is capable of inhibiting all competing centers of excitation. 2 - any stimulus is sufficient for an animal in a state of food dominance to respond to any irritation with salivation and food-procuring activity. It is the dominant that makes it possible to close the temporary connection in the cerebral cortex between neutral and vitally important events. The phenomenon of dominance is associated with illusions of attitude: we, as a rule, do not notice what we do not expect to see. Sources of materials http://school.xvatit.com/index. http://rugrad.eu/communication/blogs/Paralipomenon/1598/?commentId=18855 http://nashavlast.ru/article_description/107/1070.html http://medicinkoff.ru/page/76/ http:/ /andrey-dol.spb.ru/golovolomki/litso_saksafon.shtml http://clubs.ya.ru/4611686018427406302/replies.xml?item_no=13720 http://www.kcnlp.com.ua/illusions/2D/ http ://biology.ru/course/content/scientist/uhtonsky.html

Reflexes.

Reflexes

Unconditional

(congenital)

Conditional

(purchased)

Available from birth and passed on by inheritance.
The same for all organisms of a given species.
They do not change or disappear during life.
Adapt the body to constant conditions.
Carried out thanks to the work of the spinal cord and subcortical structures of the brain

1- nerve ending

2 – sensitive neuron

3 – interneuron

4 – motor neuron

5 - working body

Orienting reflex

Experiment: subjects are asked to read a short text. The rest of those present are watching them

While reading, the experimenter makes a loud sound.

At this moment, most subjects will stop reading and involuntarily turn their heads towards the source of the sound (orienting reflex).

Swallowing reflex

Experience: The subjects are asked to quickly make several swallowing movements in a row.

Proves that the unconditioned swallowing reflex cannot be carried out without irritation of the root of the tongue, the reflexogenic zone of this reflex. When an irritant is exposed to the root of the tongue, the act of swallowing occurs involuntarily, and a person can swallow an inedible object.

Pupillary reflex

Experiment: The subjects look towards the curtained window, observers carefully look at their pupils. The experimenter quickly changes the room's illumination

Proves that constriction of the pupils occurs reflexively in response to changes in illumination