From Big Medical Encyclopedia

APPROXIMATE AND RESEARCH REACTION (synonym orientative reflex) — active reaction of the person or animal to unexpected change of a usual situation; behavioural answer to novelty.

I. P. Pavlov called About. - and. river «reflex that it?», emphasizing with that its orientation on search of a source and the reasons of the new phenomenon, and also a «adjusting» reflex since the animal orients the body, the head and sense bodys towards an unusual irritant. O.'s essence - and. the river consists in focusing and mobilization of internal systems of an organism for examination biological (at the person often and social) the importance of an unknown factor, in ensuring readiness for necessary and adequate response actions. The lake - and. the ruble at the person receives special refraction in the form of conscious research activity.

In O. - and. rubles differ the general and specialized (specific, individual) signs of manifestation. Generalized motor reactions (start, dying down), increase in excitability of a nervous system and activation of analyzers belong to the general signs that is followed by the strengthened release of adrenaline and a number of vegetative shifts: level of blood pressure increases, cordial reductions become frequent and amplify, breath etc. changes.

Activation of c. the N of page, occurring at action of a new factor (irritant), is displayed on EEG of the person in the form of increase of an alpha rhythm and its desynchronization — at wakefulness (A-stage) or flashes of alpha fluctuations — in a poludre-motny state (B-stage). At the same time also caused answers (Vertexum potentials) are registered. At the cellular level increase is found, reduction of frequency of pulse activity of neurons in cortical and other departments of a brain is more rare.

The lake - and. the river is not always combined with active research behavior: having convinced at passive waiting of indifference of a new irritant, the person or an animal can not pay attention to it any more. The lake - and. the river can have certain «coloring» (defensive, aggressive, food, sexual, etc. To what is reflected in an orientation of behavioural reaction. Depending on a look, temperament or funkts, animal O.'s conditions - and. the river can come to the end with flight or rapprochement for contact or attack.

Forms of manifestation of O. - and. rubles considerably differ at the organisms which are at various steps of evolutionary development. The lake - and. the river at the lowest animals is expressed in the general motive excitement or, on the contrary, in dying down, concealment. With complication of a structure and functions of a nervous system specialized adjusting muscular reactions — for orientation of a body and sense bodys in the direction of an irritant arise and are improved. At the same time there is sensitization of the corresponding analyzers, concentration of attention etc. of O. - and. rubles are directed to identification not only new irritants, but also their objective parameters, already known at partial shift, napr, sound intensity with the same frequency, a color value at the same coloring, etc., and selection of signs happens up to limits of differential sensitivity of analyzers. The lake - and. the river appears both for the beginning of action of an incentive, and on its switching off.

Fiziol, patterns of implementation of O. - and. rubles at the person and the highest animals are in many respects similar. At the same time also a number of the features depending on the level of development of the highest departments of a brain, perfection of separate analyzers, their preferential ecological value is allocated (sight — at the person, monkeys, many bird species; sense of smell, hearing, a scotopia — at predators; hearing — at herbivorous; ultrasonic hearing — at dolphins, bats etc.). At high-organized animals, in particular at primacies, active research search of sources and reasons of the new phenomenon for its definition biol, the importance becomes dominating O.'s party - and. river that is expressed in irregular shapes of behavior — at anthropoids even using the elementary tools (sticks, stones and so forth). Former experience and the developed ability to initial generalizations, simultaneous and consecutive associations, to formation of primary representations and concepts fixed in memory is used for understanding and classification of new (see. Higher nervous activity ). All this already is rudiments of thinking. At last, the person has a research orientation of O. - and. river, keeping obshchebiol. bases, gains qualitatively new features in the form of conscious practical and scientific activities, aspiration to knowledge, ability to the abstracted theoretical thinking.

The lake - and. the river as fiziol, the phenomenon for the first time was described by I. M. Sechenov in the book «Reflexes of a Brain» (1863), giving an example of the «reflected» start of «the nervous lady» on unexpected knock (so-called start reflex). This reflex, I. M. Sechenov emphasized, at action of a new irritant it is shown in the fatal way», but weakens and disappears at its repetition as a result of «the detaining mechanisms», i.e. action central braking (see). Later these features of O. - and. rubles were noted and confirmed by I. P. Pavlov, and also JI. A. Orbeli, writing that O. - and. the river begins as an instinctive reflex («a fatal image»), and flows as conditional as is exposed to an ugasheniye — internal, conditioned inhibition (see. Conditioned reflex ).

O.'s implementation - and. the river is followed by braking of all current departures of an organism and a disinhibition of earlier detained. The lake - and. the river suppresses other instinctive reflexes, but if the last reach force dominants (see), i.e. cause extreme excitement of an animal (food, sexual, painful, defensive), that O. - and. the river can not be shown. Working on the mechanism of external inhibition, O. - and. the river interrupts also conditioned reflexes. Biologically it very important as the new, unknown irritant can demand concentration of attention, all forces and urgent response action. If the irritant repeatedly repeats and is indifferent, O. - and. the river dies away and the animal is returned to former occupations or to a condition of rest. The organism gets used to a new incentive, or, speaking to I. M. Sechenov's words, is learned to it to counteract. Such elementary form of education consists (according to I. P. Pavlov) in formation of a negative, i.e. inhibitory conditioned reflex.

Ugasatelny braking of O. - and. the river is considered as a type of accustoming — biologically more general manifestation of plasticity of organisms. Plasticity does accustoming by the active process allowing to adapt quickly behavior for the changed situation. Ugashenny O. - and. the river after nek-ry time - is recovered, as well as an ugashenny positive conditioned reflex in what similarity in their course is also found.

Speed of fading of O. - and. the river is connected with its expressiveness that is defined not only physical. - chemical parameters of an irritant, but also biological, in particular ecological, specifics of an incentive, and also complexity of not deciphered information which is contained in it (the last has special value for the person). The large role is played by degree of novelty, surprise and the hidden ambiguity of an incentive, and also its similarity to the irritants bearing genetically put information on usefulness or harm of this sign (peep of a mouse — for a cat, a species of a snake — for monkeys etc.).

In the course of O.'s ontogenesis - and. the river is originally observed in the form of the generalized physical activity usually connected with a food dominant. Gradually specialized installation of sense bodys, a research reflex forms, and at stronger incentive of O. - and. the river gets defensive coloring. Essential value has an appearance of stimulation. Newborn children have the greatest brake action on the sucking movements; render sound incentives, less considerable — light, olfactory, tactile. Animals (monkeys, puppies) before everything have O. - and. river on a smell and tactile stimulations.

There are different views in the relation neyrofiziol, mechanisms O. - and. Nek-ry researchers connect by river O.'s manifestation - and. river with the special «neurons of novelty» capable to react only to earlier not being found incentive.

The standard classification of O. - and. there is no river. More often they are subdivided on degree of complexity into the following categories: 1 — generalized, like start (start reflex), the general excitement or dying down; 2 — with the motivational «coloring» inherent in a condition of dominant requirement; 3 — righting reflexes; 4 — simple approximate and research reactions; 5 — active research search — at the highest animals, primacies, supplemented by use of tools — at anthropoids; 6 — the conscious research activity of the person directed to knowledge of laws of life, development of the nature and human about-va.

The lake - and. the river as one of fiziol, correlates of attention is an important component of various conditioned reflexes, thus participating in all types of century of N of. By numerous experiences it is established that O.'s presence - and. it is necessary for river on future prearranged signal for formation of uslovnoreflektorny bonds. So, training of the person is possible only at sufficient degree of attention to a subject about what to a certain extent it is possible to judge objectively by these or those indicators of O. - and. river. It is experimentally shown that training (especially children) goes more successfully when degree of novelty is high. Novelty, singularity in this case acts in itself as a factor of a reinforcement, providing formation of new uslovnoreflektorny bonds, facilitating perception and storing.

Degree of manifestation of O. - and. the river considerably depends on type and funkts, conditions of a nervous system. At unbalanced, impressionable people of O. - and. the river is excited and is disproportionate to force and degree of novelty of the perceived stimulation. On the contrary, at the phlegmatic, sluggish person O. - and. the river is shown in the weakened form. Bystry accustoming to new irritants, to an unusual situation is characteristic of balanced strong type of a nervous system that allows to react most adequately and quickly to the changing requirements of a situation. Disturbance of normal course of O. - and. the river demonstrates deterioration funkts, conditions of a nervous system, napr, as a result of overfatigue, a hyponutrient, alcoholic poisoning, drowsiness. More serious shifts indicate development or existence of these or those nervous diseases. In particular, at neurosises at the person hypererethism, vigilance in relation to a new situation, the new phenomena, the considerable size of vegetative components O. is observed - and. river, its slow and incomplete fading. At patients with schizophrenia, on the contrary, areactivity or weak expressiveness of O. is often noted - and. river, emergence instead of it defensive reactions. The lake - and. rubles are suppressed also at various depressions.

Having kept completely important biol, the value acquired in the course of evolution, O. - the item of river in activity of the person turned into powerful social factor, the range of action to-rogo stretches from manifestations of mere curiosity and passion to new impressions to the continued searches directed to knowledge of mysteries of the nature.

Bibliography: Anokhin P. K. Biology and neurophysiology of a conditioned reflex, M., 1968; To r and t and Yu. G N. Analysis of signals brain, page 98, L., 1977; The Orientative reflex and oriyentirovochnoissledovatelsky activity, under the editorship of L. G. Voronin, etc., M., 1958; Pavlov I. II. Complete works, t. 3 — 4, M. — L., 1951: With e of the p e of N about in I. M. Chosen works, t. 1 — 2, M., 1952 — 1956; Falcons E. H. Perception and conditioned reflex, M., 1958; it, Nervous model of an incentive in a reflex arc, Zhurn. vyssh. nervn. deya-teln., t. 28, century 2, page 227, 1978; S liarp-less S. Jasper H. Habituation of the arousal reaction, Brain, v. 79, p. 655, 1956.

Yu. G. Kratin.