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in biology, the complex anatomical-physiological systems that provide for the perception and analysis of all stimuli acting on animals and humans. The biological role of analyzers is to ensure the expeditious reaction of an organism to a change in its living conditions, which facilitates its more complete adaptation to the surrounding world and the maintenance of a relative constancy in its internal environment.

The concept of analyzers was introduced in physiology by the Russian physiologist I. P. Pavlov in 1909. The method of conditioning reflexes made possible objective study of analyzer activity in animals and humans. The study of analyzers contributed to the natural scientific basis of the dialectical materialist conception of perception, which, in the words of V. I. Lenin, “. . . is actually the immediate bond between consciousness and the external world, is the transformation of the energy of an external stimulus into a fact of consciousness” (Poln. sobr. soch., 5th ed., vol. 18, p. 46).

Every analyzer consists of a peripheral perceptive apparatus (receptor), the conducting part of the analyzer —which transmits information—and the higher center of the analyzer—a group of neurons in the cerebral cortex. All the sense organs (of sight, hearing, taste, and so forth) and the special receptor formations in organs, tissues, joints, blood vessels, and muscles are perceptive apparatus. Adaptation to the perception of definite types of stimuli and high sensitivity to them are characteristic of receptor devices because of their particular structures. The conducting portions of analyzers consist of a peripheral nerve and nerve cells (intercalary neurons). These cells are located in the central nervous system, except for the first two neurons of the visual, olfactory, and auditory analyzers, which are located peripherally in the corresponding sense organs.

Analysis of stimuli acting on the organism begins at the periphery. Each receptor reacts to a definite form of energy. Analysis continues in the intercalary neurons. Thus, distinguishing the color and position of an object is possible at the level of the neurons of the visual analyzer located in the interbrain. But subtle, differentiated analysis of complex, changing stimuli from the external environment takes place only in the highest centers of the analyzer—the cortex of the large hemispheres of the brain.

Analyzers play an important role in the regulation and self-regulation of the activity of organs, of physiological systems, and of the total organism. The analyzer function of the brains of animals and humans is in close mutual interaction with their synthetic functions and is characterized by great sensitivity, subtle differentiation of perceptions and broad adaptation to changes in intensity and quality of stimuli. The analytic-synthetic activity of the large hemispheres of the brain is the basis of higher nervous activity.

Study of the activities of analyzers has great theoretical and practical significance for physiology, philosophy, psychology, and medicine; it is also important for technological progress, in the planning of which the study of analyzers is concerned with engineering psychology. The following questions are relevant to the study of analyzers: how to place instruments on a control panel; what color, shape, size, frequency, and intensity their signals should be in order to be more quickly and more accurately perceived by a pilot, astronaut, dispatcher, operator, and others; what are the thresholds of perception under various conditions; and how do these thresholds change with changing conditions or with a change in the person’s condition. Thus, in the development of measuring or signaling devices, an inventory of the possibilities of various analyzers has made it possible to define the best conditions for observing them, including optimal sizes and shapes of dials, screens, and so forth and their placement on the panel.


Pavlov, I. P. Poln. sobr. soch., 2nd ed., vol. 4. Moscow, 1951. Pages 122–44.
Chernigovskii, V. N. Interotseptory. Moscow, 1962.
Gambarian, L. S. Voprosy fiziologii dvigatel’nogo analizatora. Moscow, 1962.


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